use std::cmp::min; use std::convert::Infallible; use crate::api_token::APIToken; use crate::pandoc::PandocProcessBuilder; use crate::pdfium::PdfiumInit; use async_stream::stream; use axum::extract::Query; use axum::extract::rejection::QueryRejection; use axum::response::sse::{Event, Sse}; use base64::{engine::general_purpose, Engine as _}; use calamine::{open_workbook_auto, Error as CalamineError, Reader}; use chardetng::{EncodingDetector, Iso2022JpDetection, Utf8Detection}; use docx_to_md::{DocumentContainer, ImageHandlingMode as DocumentImageHandlingMode, Metadata as DocumentMetadata, ParserConfig as DocumentParserConfig}; use encoding_rs::Encoding; use file_format::{FileFormat, Kind}; use futures::{Stream, StreamExt}; use pdfium_render::prelude::{Pdfium, PdfiumError, PdfiumInternalError}; use pptx_to_md::{DiagnosticSeverity, ImageHandlingMode, MarkdownOptions, ParserConfig, PresentationContainer, PresentationFormat, PresentationMetadata, ReadingOrder}; use serde::{Deserialize, Deserializer, Serialize}; use serde::de::{Error as SerdeError, Visitor}; use std::path::Path; use std::pin::Pin; use std::fmt; use log::{debug, error, warn}; use tokio::io::AsyncReadExt; use tokio::sync::mpsc; use tokio_stream::wrappers::ReceiverStream; #[derive(Debug, Serialize)] pub struct Chunk { pub content: String, pub stream_id: String, pub metadata: Metadata, } impl Chunk { pub fn new(content: String, metadata: Metadata) -> Self { Chunk { content, stream_id: String::new(), metadata } } /// Creates a chunk which reports a failed extraction. Errors travel through the same /// schema as content chunks, so the .NET app is able to deserialize and surface them /// instead of silently treating a failure as empty file content. pub fn from_error(error: &ExtractionError) -> Self { Chunk { content: String::new(), stream_id: String::new(), metadata: Metadata::Error { code: error.code, message: error.message.clone(), page_number: error.page_number, detected_format: error.detected_format.clone(), }, } } pub fn set_stream_id(&mut self, stream_id: &str) { self.stream_id = stream_id.to_string(); } } #[derive(Debug, Serialize)] pub enum Metadata { Text { line_number: usize }, Pdf { page_number: usize }, Spreadsheet { sheet_name: String, row_number: usize, }, Document { page_number: Option, image: Option, }, Image {}, Presentation { slide_number: u32, image: Option, }, Error { code: ExtractionErrorCode, message: String, page_number: Option, detected_format: Option, }, } /// Classifies why an extraction failed, so the .NET app can tell the user what happened /// instead of showing an empty document. #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize)] #[serde(rename_all = "SCREAMING_SNAKE_CASE")] pub enum ExtractionErrorCode { /// The request itself was malformed, e.g. a missing query parameter. InvalidRequest, FileNotFound, FileNotReadable, /// Another process holds the file open and denies us reading it. FileLocked, FormatDetectionFailed, NotAValidPdf, NotAValidSpreadsheet, PdfiumUnavailable, PdfEncrypted, PageExtractionFailed, NoTextExtracted, /// The content does not match the file extension. This is a notice, not a failure: we read /// the file according to its content and only tell the user about the wrong extension. ExtensionMismatch, /// The file was read as text, but its bytes are not text. NotTextContent, /// The file is an executable, no matter what its extension claims. ExecutableRejected, Unsupported, /// Any failure which does not carry a code of its own yet. Internal, } /// An extraction failure with a machine-readable code. It implements `std::error::Error`, /// so it travels through the existing boxed error channel and `?` keeps working for the /// error types of the underlying crates. #[derive(Debug, Clone)] pub struct ExtractionError { pub code: ExtractionErrorCode, pub message: String, pub page_number: Option, /// The format we identified by looking at the content, e.g. when it contradicts the file /// extension. The app names it so the user learns what the file really is. pub detected_format: Option, } impl ExtractionError { pub fn new(code: ExtractionErrorCode, message: impl Into) -> Self { Self { code, message: message.into(), page_number: None, detected_format: None } } pub fn on_page(code: ExtractionErrorCode, message: impl Into, page_number: usize) -> Self { Self { code, message: message.into(), page_number: Some(page_number), detected_format: None } } /// Creates an error which names the format we identified by looking at the content. pub fn with_detected_format(code: ExtractionErrorCode, message: impl Into, detected_format: &FileFormat) -> Self { Self { code, message: message.into(), page_number: None, detected_format: Some(detected_format.name().to_string()) } } /// Recovers the structured error from a boxed error. Errors which do not carry a code /// yet are reported as `Internal`, so every failure reaches the .NET app through the /// same schema. fn from_boxed(error: &(dyn std::error::Error + Send + Sync + 'static)) -> Self { match error.downcast_ref::() { Some(extraction_error) => extraction_error.clone(), None => Self::new(ExtractionErrorCode::Internal, error.to_string()), } } } impl fmt::Display for ExtractionError { fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { match self.page_number { Some(page_number) => write!(formatter, "[{:?}] page {page_number}: {}", self.code, self.message), None => write!(formatter, "[{:?}] {}", self.code, self.message), } } } impl std::error::Error for ExtractionError {} /// Detects whether a file system error means that another process holds the file open. /// /// Windows answers with `ERROR_SHARING_VIOLATION` (32) or `ERROR_LOCK_VIOLATION` (33). This also /// covers files on a network drive, because the SMB server enforces the lock and the client /// surfaces the very same codes. #[cfg(windows)] fn is_locked_error(error: &std::io::Error) -> bool { matches!(error.raw_os_error(), Some(32) | Some(33)) } /// Detects whether a file system error means that another process holds the file open. /// /// Unix has no distinct error for this. A lock held through an SMB share surfaces as a permission /// problem, which we cannot tell apart from an actual permission problem, so we never claim a file /// is locked here. #[cfg(not(windows))] fn is_locked_error(_error: &std::io::Error) -> bool { false } /// Classifies a file system error, so a file which another program holds open is reported as such /// instead of collapsing into a generic read failure. fn classify_io_error(error: &std::io::Error) -> ExtractionErrorCode { if is_locked_error(error) { return ExtractionErrorCode::FileLocked; } match error.kind() { std::io::ErrorKind::NotFound => ExtractionErrorCode::FileNotFound, std::io::ErrorKind::InvalidData => ExtractionErrorCode::FormatDetectionFailed, _ => ExtractionErrorCode::FileNotReadable, } } #[derive(Debug, Serialize)] pub struct Base64Image { pub id: String, pub content: String, pub segment: usize, pub is_end: bool, pub media_type: Option, } impl Base64Image { fn new(id: String, content: String, segment: usize, is_end: bool, media_type: Option) -> Self { Self { id, content, segment, is_end, media_type } } } const TO_MARKDOWN: &str = "markdown"; /// Pandoc's markup-free output format. We do not use it as content, only to find out whether a /// conversion produced any readable text at all. const PANDOC_PLAIN: &str = "plain"; const DOCX: &str = "docx"; const ODT: &str = "odt"; const HTML: &str = "html"; const IMAGE_SEGMENT_SIZE_IN_CHARS: usize = 8_192; // equivalent to ~ 5500 token /// Every PDF file starts with this signature. const PDF_MAGIC: &[u8] = b"%PDF-"; /// How many bytes we probe to verify the PDF signature. The few extra bytes beyond the /// signature itself make the diagnostics useful when the signature does not match. const PDF_HEADER_PROBE_SIZE: u64 = 8; /// Last-resort payload used when even an error event cannot be serialized. It keeps the /// chunk schema intact, so the .NET app never has to parse a bare string. const FALLBACK_ERROR_EVENT_JSON: &str = r#"{"content":"","stream_id":"","metadata":{"Error":{"code":"INTERNAL","message":"The extraction error could not be serialized.","page_number":null,"detected_format":null}}}"#; type Result = std::result::Result>; type ChunkStream = Pin> + Send>>; #[derive(Deserialize)] pub struct ExtractDataQuery { path: String, stream_id: String, #[serde(deserialize_with = "deserialize_bool_case_insensitive")] extract_images: bool, } fn deserialize_bool_case_insensitive<'de, D>(deserializer: D) -> std::result::Result where D: Deserializer<'de>, { struct BoolVisitor; impl<'de> Visitor<'de> for BoolVisitor { type Value = bool; fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result { formatter.write_str("a boolean value") } fn visit_bool(self, value: bool) -> std::result::Result { Ok(value) } fn visit_str(self, value: &str) -> std::result::Result where E: SerdeError, { match value.to_ascii_lowercase().as_str() { "true" | "1" => Ok(true), "false" | "0" => Ok(false), _ => Err(E::invalid_value(serde::de::Unexpected::Str(value), &self)), } } } deserializer.deserialize_any(BoolVisitor) } /// Reports an extraction failure as a schema-conformant SSE event, so the .NET app is able /// to deserialize it like any other chunk. fn error_event(error: &ExtractionError, stream_id: Option<&str>) -> Event { let mut chunk = Chunk::from_error(error); if let Some(stream_id) = stream_id { chunk.set_stream_id(stream_id); } Event::default().json_data(&chunk).unwrap_or_else(|serialization_error| { error!("Failed to serialize an extraction error event: {serialization_error}"); Event::default().data(FALLBACK_ERROR_EVENT_JSON) }) } pub async fn extract_data( _token: APIToken, query: std::result::Result, QueryRejection>, ) -> Sse>> { let query = match query { Ok(Query(query)) => Ok(query), Err(e) => { let message = format!("Invalid query for '/retrieval/fs/extract': {e}"); warn!("{message}"); Err(ExtractionError::new(ExtractionErrorCode::InvalidRequest, message)) }, }; let stream = stream! { match query { Ok(query) => { let stream_result = stream_data(&query.path, query.extract_images, &query.stream_id).await; let id_ref = &query.stream_id; let path_ref = &query.path; match stream_result { Ok(mut stream) => { while let Some(chunk) = stream.next().await { match chunk { Ok(mut chunk) => { chunk.set_stream_id(id_ref); yield Ok(Event::default().json_data(&chunk).unwrap_or_else(|e| { error!("Failed to serialize a content chunk for '{path_ref}': {e}"); error_event(&ExtractionError::new(ExtractionErrorCode::Internal, format!("Failed to serialize a content chunk: {e}")), Some(id_ref)) })); }, Err(e) => { let extraction_error = ExtractionError::from_boxed(e.as_ref()); error!("Extraction failed for '{path_ref}': {extraction_error}"); yield Ok(error_event(&extraction_error, Some(id_ref))); break; }, } } }, Err(e) => { let extraction_error = ExtractionError::from_boxed(e.as_ref()); error!("Could not start the extraction stream for '{path_ref}': {extraction_error}"); yield Ok(error_event(&extraction_error, Some(id_ref))); } }; }, Err(extraction_error) => { yield Ok(error_event(&extraction_error, None)); }, } }; Sse::new(stream) } /// How a file is read. /// /// Deriving the route from the extension and from the content separately is what lets us notice /// when the two disagree, instead of trusting a possibly wrong extension blindly. #[derive(Debug, Clone, Copy, PartialEq, Eq)] enum ExtractionRoute { Pdf, Docx, Odt, PandocHtml, PresentationPptx, PresentationOdp, Spreadsheet, Csv, Text, Image, /// The file is an executable and is never read. Executable, /// A format we recognize but have no reader for, e.g. the legacy binary Office formats. Unsupported, } /// Derives the route from the file extension. fn route_from_extension(ext: &str) -> Option { match ext { "pdf" => Some(ExtractionRoute::Pdf), DOCX => Some(ExtractionRoute::Docx), ODT => Some(ExtractionRoute::Odt), HTML | "htm" => Some(ExtractionRoute::PandocHtml), "csv" | "tsv" => Some(ExtractionRoute::Csv), "pptx" => Some(ExtractionRoute::PresentationPptx), "odp" => Some(ExtractionRoute::PresentationOdp), "xlsx" | "ods" | "xls" | "xlsm" | "xlsb" | "xla" | "xlam" => Some(ExtractionRoute::Spreadsheet), "jpg" | "jpeg" | "png" | "gif" | "bmp" | "tiff" | "svg" | "webp" | "heic" => Some(ExtractionRoute::Image), // // Everything else claims nothing in particular. Text formats end up here on purpose: // their content cannot be identified beyond "this is text", so there is nothing to // contradict. Every extension which does have a reader must be listed above, otherwise // a correctly named file looks like a mismatch. // _ => None, } } /// Derives the route from the content we identified. /// /// `None` means the content does not point at any particular reader. Such a file keeps whatever /// its extension asks for, and the text reader decides whether the bytes are readable at all. fn route_from_content(fmt: FileFormat) -> Option { match fmt { FileFormat::PortableDocumentFormat => Some(ExtractionRoute::Pdf), FileFormat::OfficeOpenXmlDocument => Some(ExtractionRoute::Docx), FileFormat::OpendocumentText => Some(ExtractionRoute::Odt), FileFormat::HypertextMarkupLanguage => Some(ExtractionRoute::PandocHtml), FileFormat::OfficeOpenXmlPresentation => Some(ExtractionRoute::PresentationPptx), FileFormat::OpendocumentPresentation => Some(ExtractionRoute::PresentationOdp), // Calamine reads the legacy binary spreadsheet format as well: FileFormat::OfficeOpenXmlSpreadsheet | FileFormat::OpendocumentSpreadsheet | FileFormat::MicrosoftExcelSpreadsheet => Some(ExtractionRoute::Spreadsheet), FileFormat::PlainText => Some(ExtractionRoute::Text), // // The legacy binary Word and PowerPoint formats have no reader here: pptx_to_md only // handles PPTX and ODP, and docx_to_md only reads the XML-based DOCX and ODT. Saying so // is better than handing the file to a reader which is bound to fail. // FileFormat::MicrosoftWordDocument | FileFormat::MicrosoftPowerpointPresentation => Some(ExtractionRoute::Unsupported), _ => match fmt.kind() { Kind::Executable => Some(ExtractionRoute::Executable), Kind::Image => Some(ExtractionRoute::Image), Kind::Ebook | Kind::Archive | Kind::Compressed => Some(ExtractionRoute::Unsupported), _ => None, }, } } async fn stream_data(file_path: &str, extract_images: bool, stream_id: &str) -> Result { if !Path::new(file_path).exists() { error!("File does not exist: '{file_path}'"); return Err(ExtractionError::new(ExtractionErrorCode::FileNotFound, format!("The file does not exist: '{file_path}'.")).into()); } let file_path_clone = file_path.to_owned(); let fmt = match FileFormat::from_file(&file_path_clone) { Ok(format) => format, Err(error) => { // // Detecting the format opens the file, so this is the first place a file which another // program holds open fails. Reporting that as a format problem would send the user // looking in the wrong direction, hence we classify the error instead. // let code = classify_io_error(&error); error!("Failed to read '{file_path}' while determining its file format ({code:?}): {error}"); return Err(ExtractionError::new(code, format!("The file could not be read: {error}")).into()); }, }; let ext = Path::new(file_path) .extension() .and_then(|extension| extension.to_str()) .map(str::to_ascii_lowercase) .unwrap_or_default(); // The size is part of the diagnostics: a truncated or not-yet-available file on a network // share is what tells a broken extraction apart from a document without text. let file_size = match tokio::fs::metadata(file_path).await { Ok(metadata) => format!("{} bytes", metadata.len()), Err(error) => format!("unknown size ({error})"), }; debug!("Extracting data from file: '{file_path}', {file_size}, format: '{fmt:?}', extension: '{ext}'"); let extension_route = route_from_extension(ext.as_str()); let content_route = route_from_content(fmt); // // The content decides whenever it points at a specific reader and contradicts the extension. // `Text` is excluded on purpose: it is the least specific answer, and letting it win would // cost a `.csv` its CSV fence. When the content says nothing, the extension keeps its say and // the text reader decides whether the bytes are readable at all. // let content_is_specific = matches!(content_route, Some(route) if route != ExtractionRoute::Text); let content_contradicts_extension = content_is_specific && content_route != extension_route; let route = match (extension_route, content_route) { _ if content_contradicts_extension => content_route.unwrap(), (Some(from_extension), _) => from_extension, (None, Some(from_content)) => from_content, (None, None) => ExtractionRoute::Text, }; debug!("Reading '{file_path}' via {route:?} (extension: {extension_route:?}, content: {content_route:?})."); match route { ExtractionRoute::Executable => { error!("Refused to read '{file_path}': its content is an executable ({name}).", name = fmt.name()); return Err(ExtractionError::with_detected_format( ExtractionErrorCode::ExecutableRejected, format!("The file is an executable ({name}), which is never read.", name = fmt.name()), &fmt, ).into()); }, ExtractionRoute::Unsupported => { return Err(ExtractionError::with_detected_format( ExtractionErrorCode::Unsupported, format!("The format '{name}' is not supported.", name = fmt.name()), &fmt, ).into()); }, ExtractionRoute::Image if !extract_images => { return Err(ExtractionError::new(ExtractionErrorCode::Unsupported, "Image extraction is disabled.").into()); }, _ => {}, } let stream = match route { ExtractionRoute::Pdf => stream_pdf(file_path).await?, ExtractionRoute::Docx | ExtractionRoute::Odt => stream_document(file_path, extract_images, stream_id).await?, ExtractionRoute::PandocHtml => convert_with_pandoc(file_path, HTML, TO_MARKDOWN).await?, ExtractionRoute::PresentationPptx => stream_presentation(file_path, extract_images, PresentationFormat::Pptx).await?, ExtractionRoute::PresentationOdp => stream_presentation(file_path, extract_images, PresentationFormat::Odp).await?, ExtractionRoute::Spreadsheet => stream_spreadsheet_as_csv(file_path).await?, ExtractionRoute::Csv => stream_text_file(file_path, true, Some("csv".to_string())).await?, ExtractionRoute::Text => stream_text_file(file_path, false, None).await?, ExtractionRoute::Image => chunk_image(file_path).await?, // Handled above, before any reader was chosen: ExtractionRoute::Executable | ExtractionRoute::Unsupported => unreachable!(), }; // // The file was readable, but not as its extension claims. We prepend a notice so the user // learns what the file really is, while the content itself is read correctly. // if content_contradicts_extension { warn!("The content of '{file_path}' is '{name}', which does not match its extension '{ext}'.", name = fmt.name()); let notice = Chunk::from_error(&ExtractionError::with_detected_format( ExtractionErrorCode::ExtensionMismatch, format!("The content is '{name}', which does not match the file extension '{ext}'.", name = fmt.name()), &fmt, )); let notice_stream = stream! { yield Ok(notice); }; return Ok(Box::pin(notice_stream.chain(stream))); } Ok(Box::pin(stream)) } /// How many bytes we inspect for NUL bytes to tell binary content from text. const BINARY_PROBE_SIZE: usize = 8_192; /// Reads a text file and decodes it, no matter which encoding it uses. /// /// Insisting on UTF-8 is not enough in practice: text files written on Windows are frequently /// encoded in Windows-1252, where umlauts are single bytes which UTF-8 rejects. Such a file used /// to look like it was not text at all. async fn read_text_file(file_path: &str) -> Result { let bytes = tokio::fs::read(file_path).await.map_err(|error| ExtractionError::new( classify_io_error(&error), format!("The file could not be read: {error}"), ))?; // // A byte order mark is authoritative and also covers UTF-16, which the detector below does not // recognize. We therefore check it first and let `decode` act on it. // if let Some((encoding, _)) = Encoding::for_bom(&bytes) { let (text, _, _) = encoding.decode(&bytes); debug!("Decoded '{file_path}' as {name}, chosen by its byte order mark.", name = encoding.name()); return Ok(text.into_owned()); } // // Without a byte order mark, every byte sequence decodes into *something*, so the decoder can // no longer tell us that a file is binary. NUL bytes do: they do not occur in text, and after // the check above no UTF-16 file can reach this point. // let probe_length = min(bytes.len(), BINARY_PROBE_SIZE); if bytes[..probe_length].contains(&0) { return Err(ExtractionError::new( ExtractionErrorCode::NotTextContent, "The file contains binary data and is not a text file.", ).into()); } // // Both options are about untrusted web content which may run scripts, which is not what we // read here: these are local files the user picked, so allowing both guesses gives the better // detection. // let mut detector = EncodingDetector::new(Iso2022JpDetection::Allow); detector.feed(&bytes, true); let (text, encoding, had_errors) = detector.guess(None, Utf8Detection::Allow).decode(&bytes); if had_errors { warn!("Decoding '{file_path}' as {name} replaced malformed sequences.", name = encoding.name()); } else { debug!("Decoded '{file_path}' as {name}.", name = encoding.name()); } Ok(text.into_owned()) } async fn stream_text_file(file_path: &str, use_md_fences: bool, fence_language: Option) -> Result { let text = read_text_file(file_path).await?; let mut line_number = 0; let stream = stream! { if use_md_fences { match fence_language { Some(lang) if lang.trim().is_empty() => { yield Ok(Chunk::new("```".to_string(), Metadata::Text { line_number })); }, Some(lang) => { yield Ok(Chunk::new(format!("```{}", lang.trim()), Metadata::Text { line_number })); }, None => { yield Ok(Chunk::new("```".to_string(), Metadata::Text { line_number })); } }; } for line in text.lines() { line_number += 1; yield Ok(Chunk::new( line.to_string(), Metadata::Text { line_number } )); } if use_md_fences { yield Ok(Chunk::new("```\n".to_string(), Metadata::Text { line_number })); } }; Ok(Box::pin(stream)) } /// Verifies the file really is a PDF before handing it to PDFium. Without this check, a file /// which only carries the `.pdf` extension, or whose bytes are not available, would end up in /// the text branch and silently produce empty content. async fn ensure_pdf_header(file_path: &str) -> Result<()> { let file = tokio::fs::File::open(file_path).await.map_err(|error| ExtractionError::new( classify_io_error(&error), format!("The file could not be opened: {error}"), ))?; let file_size = file.metadata().await.map_err(|error| ExtractionError::new( classify_io_error(&error), format!("The file size could not be read: {error}"), ))?.len(); let mut header = Vec::with_capacity(PDF_HEADER_PROBE_SIZE as usize); file.take(PDF_HEADER_PROBE_SIZE).read_to_end(&mut header).await.map_err(|error| ExtractionError::new( classify_io_error(&error), format!("The first bytes of the file could not be read: {error}"), ))?; if header.starts_with(PDF_MAGIC) { return Ok(()); } let header_hex = header.iter().map(|byte| format!("{byte:02x}")).collect::>().join(" "); error!("The file '{file_path}' does not start with the PDF signature; size: {file_size} bytes, first bytes: [{header_hex}]."); Err(ExtractionError::new( ExtractionErrorCode::NotAValidPdf, format!("The file does not start with the PDF signature. Size: {file_size} bytes, first bytes: [{header_hex}]."), ).into()) } /// Classifies why PDFium refused to open a document, so the cause reaches the user instead of /// collapsing into a generic failure. fn classify_pdf_load_error(error: &PdfiumError) -> ExtractionError { let code = match error { PdfiumError::PdfiumLibraryInternalError(internal_error) => match internal_error { // The document is encrypted or its security settings forbid access: PdfiumInternalError::PasswordError | PdfiumInternalError::SecurityError => ExtractionErrorCode::PdfEncrypted, // Pdfium could not read the file itself, e.g. because a network share went away: PdfiumInternalError::FileError => ExtractionErrorCode::FileNotReadable, _ => ExtractionErrorCode::NotAValidPdf, }, _ => ExtractionErrorCode::NotAValidPdf, }; ExtractionError::new(code, format!("The PDF could not be opened: {error}")) } async fn stream_pdf(file_path: &str) -> Result { ensure_pdf_header(file_path).await?; let path = file_path.to_owned(); let (tx, rx) = mpsc::channel(10); tokio::task::spawn_blocking(move || { let pdfium = match Pdfium::ai_studio_init() { Ok(pdfium) => pdfium, Err(e) => { let _ = tx.blocking_send(Err(ExtractionError::new( ExtractionErrorCode::PdfiumUnavailable, format!("The PDF engine could not be initialized: {e}"), ).into())); return; } }; let doc = match pdfium.load_pdf_from_file(&path, None) { Ok(document) => document, Err(e) => { let _ = tx.blocking_send(Err(classify_pdf_load_error(&e).into())); return; } }; let mut number_of_pages = 0; let mut number_of_characters = 0; let mut number_of_failed_pages = 0; let mut receiver_gone = false; for (num_page, page) in doc.pages().iter().enumerate() { let page_number = num_page + 1; number_of_pages = page_number; let content = match page.text().map(|t| t.all()) { Ok(text_content) => text_content, Err(e) => { // // A single unreadable page must not end the document: we report it as a // non-fatal error chunk and continue with the next page. Sending it as an // `Err` would stop the consumer and silently truncate everything after it. // number_of_failed_pages += 1; warn!("The text of page {page_number} of '{path}' could not be extracted: {e}"); if tx.blocking_send(Ok(Chunk::from_error(&ExtractionError::on_page( ExtractionErrorCode::PageExtractionFailed, format!("The text of page {page_number} could not be extracted: {e}"), page_number, )))).is_err() { receiver_gone = true; break; } continue; } }; number_of_characters += content.chars().count(); if tx.blocking_send(Ok(Chunk::new( content, Metadata::Pdf { page_number } ))).is_err() { receiver_gone = true; break; } } if receiver_gone { debug!("The consumer stopped reading the PDF stream of '{path}' after {number_of_pages} page(s)."); return; } debug!("Extracted {number_of_characters} character(s) from {number_of_pages} page(s) of '{path}'; failed pages: {number_of_failed_pages}."); // // Without this marker, a PDF without a text layer and a broken extraction both arrive as // an empty document, and the AI would answer as if the file had no content at all. // if number_of_characters == 0 { warn!("No text could be extracted from '{path}': {number_of_pages} page(s), {number_of_failed_pages} failed page(s). The PDF may consist of scanned images without a text layer."); let _ = tx.blocking_send(Ok(Chunk::from_error(&ExtractionError::new( ExtractionErrorCode::NoTextExtracted, format!("No text could be extracted from {number_of_pages} page(s). The PDF may consist of scanned images without a text layer."), )))); } }); Ok(Box::pin(ReceiverStream::new(rx))) } /// Classifies a spreadsheet failure, so an unreadable file, e.g. on a network share which went /// away, is not reported as a corrupt workbook. fn classify_spreadsheet_error_code(error: &CalamineError) -> ExtractionErrorCode { match error { CalamineError::Io(io_error) => classify_io_error(io_error), _ => ExtractionErrorCode::NotAValidSpreadsheet, } } async fn stream_spreadsheet_as_csv(file_path: &str) -> Result { let path = file_path.to_owned(); let (tx, rx) = mpsc::channel(10); tokio::task::spawn_blocking(move || { let mut workbook = match open_workbook_auto(&path) { Ok(w) => w, Err(e) => { let _ = tx.blocking_send(Err(ExtractionError::new( classify_spreadsheet_error_code(&e), format!("The spreadsheet could not be opened: {e}"), ).into())); return; } }; for sheet_name in workbook.sheet_names() { let range = match workbook.worksheet_range(&sheet_name) { Ok(r) => r, Err(e) => { // // One unreadable sheet must not end the workbook: we report it as a non-fatal // error chunk and continue with the next sheet. Sending it as an `Err` would // stop the consumer and silently drop all remaining sheets. // warn!("The sheet '{sheet_name}' of '{path}' could not be read: {e}"); if tx.blocking_send(Ok(Chunk::from_error(&ExtractionError::new( classify_spreadsheet_error_code(&e), format!("The sheet '{sheet_name}' could not be read: {e}"), )))).is_err() { return; } continue; } }; let mut row_idx = 0; tx.blocking_send(Ok(Chunk::new( "```csv".to_string(), Metadata::Spreadsheet { sheet_name: sheet_name.clone(), row_number: row_idx, } ))).ok(); for row in range.rows() { row_idx += 1; let content = row.iter() .map(|cell| cell.to_string()) .collect::>() .join(","); if tx.blocking_send(Ok(Chunk::new( content, Metadata::Spreadsheet { sheet_name: sheet_name.clone(), row_number: row_idx, } ))).is_err() { return; } } tx.blocking_send(Ok(Chunk::new( "```".to_string(), Metadata::Spreadsheet { sheet_name: sheet_name.clone(), row_number: row_idx, } ))).ok(); } }); Ok(Box::pin(ReceiverStream::new(rx))) } async fn convert_with_pandoc( file_path: &str, from: &str, to: &str, ) -> Result { let output = PandocProcessBuilder::new() .with_input_file(file_path) .with_input_format(from) .with_output_format(to) .build() .command.output().await?; let exit_code = output.status.code(); let stderr_text = String::from_utf8_lossy(&output.stderr).trim().to_string(); debug!("Pandoc converted '{file_path}' from '{from}' to '{to}': exit={exit_code:?}, {stdout_length} byte(s) of output.", stdout_length = output.stdout.len()); if !stderr_text.is_empty() { warn!("Pandoc reported while converting '{file_path}': {stderr_text}"); } if !output.status.success() { return Err(ExtractionError::new( ExtractionErrorCode::Internal, format!("Pandoc failed with exit code {exit_code:?}: {stderr_text}"), ).into()); } let content = String::from_utf8(output.stdout).map_err(|e| ExtractionError::new( ExtractionErrorCode::Internal, format!("The output of Pandoc was not valid UTF-8: {e}"), ))?; // // Pandoc succeeded, yet nothing came out. Passing that on as content would hand an empty // document to the AI, which is exactly what this whole path must not do. // if content.trim().is_empty() || !pandoc_found_readable_text(file_path, from, &content).await { return Err(ExtractionError::new( ExtractionErrorCode::NoTextExtracted, format!("Pandoc read the file without finding any readable text{separator}{stderr_text}", separator = if stderr_text.is_empty() { "." } else { ": " }), ).into()); } let stream = stream! { yield Ok(Chunk::new( content, Metadata::Document { page_number: None, image: None, } )); }; Ok(Box::pin(stream)) } /// Decides whether a conversion produced actual text rather than just structure. /// /// HTML is the one input where markup can masquerade as content: a page which builds its text with /// scripts converts into nothing but fenced divs and class names. That looks like content, yet it /// says nothing, and the AI would be asked to work with it. Pandoc's plain output settles the /// question, because it carries no markup at all. Documents such as `.docx` carry their text /// statically, so the check above is enough for them and they are spared the extra conversion. async fn pandoc_found_readable_text(file_path: &str, from: &str, content: &str) -> bool { if from != HTML { return true; } let output = PandocProcessBuilder::new() .with_input_file(file_path) .with_input_format(from) .with_output_format(PANDOC_PLAIN) .build() .command.output().await; match output { Ok(output) if output.status.success() => { let has_text = !String::from_utf8_lossy(&output.stdout).trim().is_empty(); if !has_text { warn!("'{file_path}' converted into {length} character(s) of pure structure without any readable text.", length = content.trim().len()); } has_text }, // // We could not find out, so we do not claim the file is empty. The content we already have // is the better answer than an error we cannot justify. // Ok(output) => { warn!("Could not check '{file_path}' for readable text, Pandoc exited with {code:?}.", code = output.status.code()); true }, Err(e) => { warn!("Could not check '{file_path}' for readable text: {e}"); true }, } } async fn chunk_image(file_path: &str) -> Result { let data = tokio::fs::read(file_path).await?; let base64 = general_purpose::STANDARD.encode(&data); let stream = stream! { yield Ok(Chunk::new( base64, Metadata::Image {}, )); }; Ok(Box::pin(stream)) } async fn stream_document(file_path: &str, extract_images: bool, stream_id: &str) -> Result { let path = Path::new(file_path).to_owned(); let stream_id = stream_id.to_owned(); let parser_config = DocumentParserConfig::builder() .extract_images(extract_images) .compress_images(true) .quality(75) .image_handling_mode(DocumentImageHandlingMode::Manually) .include_document_metadata(true) .include_headers_footers(true) .include_footnotes(true) .include_endnotes(true) .include_comments(true) .include_page_number_as_comment(false) .build(); let (tx, rx) = mpsc::channel(32); let worker_error_tx = tx.clone(); // Page iteration performs synchronous ZIP/XML work and image compression, // so the complete producer must stay outside Tokio's asynchronous workers. let worker = tokio::task::spawn_blocking(move || { let document = match DocumentContainer::open(&path, parser_config) { Ok(document) => document, Err(e) => { error!("The document '{path:?}' could not be opened: {e}"); let _ = tx.blocking_send(Err(ExtractionError::new( ExtractionErrorCode::FileNotReadable, format!("The document could not be read: {e}"), ).into())); return; }, }; let mut metadata_md = document_metadata_to_markdown(document.metadata()); let pages = match document.iter_pages() { Ok(pages) => pages, Err(e) => { error!("The pages of the document '{path:?}' could not be read: {e}"); let _ = tx.blocking_send(Err(ExtractionError::new( ExtractionErrorCode::FileNotReadable, format!("The pages of the document could not be read: {e}"), ).into())); return; }, }; let mut number_of_pages = 0; let mut number_of_characters = 0; // // A failing page ends the whole document here, unlike a PDF page: the page iterator gives // up for good once it hit an error, so everything behind that page is lost as well. This // is why neither failure below reports `PageExtractionFailed`. That code means that a // single page is missing while the rest stays usable, and the app would hand the truncated // document to the AI on those grounds. // for page_result in pages { let page = match page_result { Ok(page) => page, Err(e) => { error!("A page of the document '{path:?}' could not be read: {e}"); let _ = tx.blocking_send(Err(ExtractionError::new( ExtractionErrorCode::Internal, format!("A page of the document could not be read: {e}"), ).into())); return; }, }; let mut content = match page.to_markdown() { Ok(content) => content, Err(e) => { error!("Page {page_number} of the document '{path:?}' could not be converted: {e}", page_number = page.page_number); let _ = tx.blocking_send(Err(ExtractionError::new( ExtractionErrorCode::Internal, format!("Page {page_number} of the document could not be converted: {e}", page_number = page.page_number), ).into())); return; }, }; number_of_pages = page.page_number; number_of_characters += content.chars().count(); if let Some(metadata) = metadata_md.take() { content = format!("{metadata}\n\n{content}"); } if tx.blocking_send(Ok(Chunk::new(content, Metadata::Document { page_number: Some(page.page_number), image: None, }))).is_err() { return; } for image in page.images.values() { let base64_data = image.base64(); let image_id = format!("{stream_id}-{}-{}", page.page_number, image.id); let mut offset = 0; let mut segment_index = 0; while offset < base64_data.len() { let end = min(offset + IMAGE_SEGMENT_SIZE_IN_CHARS, base64_data.len()); let base64_image = Base64Image::new(image_id.clone(), base64_data[offset..end].to_string(), segment_index, end == base64_data.len(), Some(image.media_type.clone())); if tx.blocking_send(Ok(Chunk::new(String::new(), Metadata::Document { page_number: Some(page.page_number), image: Some(base64_image), }))).is_err() { return; } offset = end; segment_index += 1; } } } debug!("Extracted {number_of_characters} character(s) from {number_of_pages} page(s) of '{path:?}'."); // // Without this marker, a document without any text and a broken extraction both arrive as // an empty document, and the AI would answer as if the file had no content at all. // if number_of_characters == 0 { warn!("No text could be extracted from '{path:?}': {number_of_pages} page(s)."); let _ = tx.blocking_send(Ok(Chunk::from_error(&ExtractionError::new( ExtractionErrorCode::NoTextExtracted, format!("No text could be extracted from {number_of_pages} page(s) of the document."), )))); } }); tokio::spawn(async move { if let Err(e) = worker.await { let _ = worker_error_tx.send(Err(ExtractionError::new( ExtractionErrorCode::Internal, format!("The document parser task failed: {e}"), ).into())).await; } }); Ok(Box::pin(ReceiverStream::new(rx))) } async fn stream_presentation(file_path: &str, extract_images: bool, format: PresentationFormat) -> Result { let path = Path::new(file_path).to_owned(); let parser_config = ParserConfig::builder() .extract_images(extract_images) .compress_images(true) .quality(75) .image_handling_mode(ImageHandlingMode::Manually) .include_presentation_metadata(true) .build(); let markdown_options = MarkdownOptions { reading_order: ReadingOrder::Spatial, include_slide_number_as_comment: true, include_speaker_notes: true, include_comments: true, render_unsupported_comments: true, }; let mut streamer = tokio::task::spawn_blocking(move || { PresentationContainer::open_as(&path, parser_config, format).map_err(|e| Box::new(e) as Box) }).await??; let (tx, rx) = mpsc::channel(32); let worker_error_tx = tx.clone(); // Slide iteration performs synchronous ZIP/XML work and image compression, // so the complete producer must stay outside Tokio's asynchronous workers. let worker = tokio::task::spawn_blocking(move || { let mut metadata_md = presentation_metadata_to_markdown(streamer.metadata()); for slide_result in streamer.iter_slides() { let slide = match slide_result { Ok(slide) => slide, Err(e) => { let _ = tx.blocking_send(Err(Box::new(e) as Box)); return; }, }; for diagnostic in &slide.diagnostics { let source = diagnostic.source.as_deref().unwrap_or("presentation"); match diagnostic.severity { DiagnosticSeverity::Warning => warn!( "Presentation slide {} warning in '{}': {}", slide.slide_number, source, diagnostic.message ), DiagnosticSeverity::Error => error!( "Presentation slide {} error in '{}': {}", slide.slide_number, source, diagnostic.message ), } } let mut content = match slide.to_markdown(&markdown_options) { Ok(content) => content, Err(e) => { let _ = tx.blocking_send(Err(Box::new(e) as Box)); return; }, }; if let Some(metadata) = metadata_md.take() { content = format!("{metadata}\n\n{content}"); } let chunk = Chunk::new( content, Metadata::Presentation { slide_number: slide.slide_number, image: None, } ); if tx.blocking_send(Ok(chunk)).is_err() { return; } if let Some(images) = slide.load_images_manually() { for image in images.iter() { let base64_data = &image.base64_content; let total_length = base64_data.len(); let mut offset = 0; let mut segment_index = 0; while offset < total_length { let end = min(offset + IMAGE_SEGMENT_SIZE_IN_CHARS, total_length); let segment_content = &base64_data[offset..end]; let is_end = end == total_length; let base64_image = Base64Image::new( image.img_ref.id.clone(), segment_content.to_string(), segment_index, is_end, None, ); let chunk = Chunk::new( String::new(), Metadata::Presentation { slide_number: slide.slide_number, image: Some(base64_image), } ); if tx.blocking_send(Ok(chunk)).is_err() { return; } offset = end; segment_index += 1; } } } } }); tokio::spawn(async move { if let Err(e) = worker.await { let _ = worker_error_tx.send(Err(format!("Presentation parser task failed: {e}").into())).await; } }); Ok(Box::pin(ReceiverStream::new(rx))) } fn presentation_metadata_to_markdown(metadata: &PresentationMetadata) -> Option { let mut fields = Vec::new(); push_presentation_metadata_field(&mut fields, "Title", metadata.title.as_deref()); push_presentation_metadata_field(&mut fields, "Author", metadata.author.as_deref()); push_presentation_metadata_field(&mut fields, "Last Modified By", metadata.last_modified_by.as_deref()); push_presentation_metadata_field(&mut fields, "Subject", metadata.subject.as_deref()); push_presentation_metadata_field(&mut fields, "Description", metadata.description.as_deref()); if !metadata.keywords.is_empty() { fields.push(format!( "Keywords: {}", sanitize_presentation_metadata_value(&metadata.keywords.join("; ")) )); } push_presentation_metadata_field(&mut fields, "Created", metadata.created_at.as_deref()); push_presentation_metadata_field(&mut fields, "Modified", metadata.modified_at.as_deref()); if fields.is_empty() { None } else { Some(format!( "", fields.join("\n") )) } } fn document_metadata_to_markdown(metadata: &DocumentMetadata) -> Option { let mut fields = Vec::new(); push_presentation_metadata_field(&mut fields, "Title", metadata.title.as_deref()); push_presentation_metadata_field(&mut fields, "Subject", metadata.subject.as_deref()); push_presentation_metadata_field(&mut fields, "Author", metadata.author.as_deref()); push_presentation_metadata_field(&mut fields, "Last Modified By", metadata.last_modified_by.as_deref()); push_presentation_metadata_field(&mut fields, "Description", metadata.description.as_deref()); if !metadata.keywords.is_empty() { fields.push(format!("Keywords: {}", sanitize_presentation_metadata_value(&metadata.keywords.join("; ")))); } push_presentation_metadata_field(&mut fields, "Created", metadata.created_at.as_deref()); push_presentation_metadata_field(&mut fields, "Modified", metadata.modified_at.as_deref()); for (name, value) in &metadata.custom { fields.push(format!("Custom {name}: {}", sanitize_presentation_metadata_value(value))); } if fields.is_empty() { None } else { Some(format!("", fields.join("\n"))) } } fn push_presentation_metadata_field(fields: &mut Vec, label: &str, value: Option<&str>) { if let Some(value) = value { fields.push(format!( "{label}: {}", sanitize_presentation_metadata_value(value) )); } } fn sanitize_presentation_metadata_value(value: &str) -> String { value .split_whitespace() .collect::>() .join(" ") .replace("--", "--") }