Refactor: migrate pdf_parser.py to golang (#16323)

### What problem does this PR solve? Http API based on onnx model. pdf_parser.py to golang ### Type of change - [x] Refactoring
2026-08-04 14:50:30 +08:00 · 2026-06-25 20:16:16 +08:00
parent c7052f4dd1
commit 304d9e02bb
98 changed files with 24591 additions and 8 deletions
--- a/internal/deepdoc/parser/pdf/position.go
+++ b/internal/deepdoc/parser/pdf/position.go
@@ -0,0 +1,110 @@
+package parser
+
+import (
+	"fmt"
+	"log/slog"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// @@ page position tag regex patterns.
+//
+// Python: pdf_parser.py:1868 remove_tag, 1872 extract_positions
+
+// posTagPattern matches the full @@...## tag including coordinates.
+// Format: @@{page_range}\t{left}\t{right}\t{top}\t{bottom}##
+var posTagPattern = regexp.MustCompile(`@@[0-9-]+\t[0-9.\t]+##`)
+
+// ExtractPositions parses @@ position tags from a text string.
+//
+// Each tag has format:
+//
+//	@@{page_range}\t{left}\t{right}\t{top}\t{bottom}##
+//
+// page_range can be a single page ("3") or a range ("0-2").
+// Pages are zero-indexed in the returned values (subtracting 1 from PDF page numbers).
+//
+// Python: pdf_parser.py:1872 extract_positions()
+//
+// Example:
+//
+//	text := "Some text @@0-1\t50.0\t300.0\t200.0\t400.0## more text"
+//	poss := ExtractPositions(text)
+//	// poss[0] = Position{PageNumbers: [-1, 0], Left: 50.0, Right: 300.0, Top: 200.0, Bottom: 400.0}
+func ExtractPositions(text string) []Position {
+	var poss []Position
+	for _, tag := range posTagPattern.FindAllString(text, -1) {
+		cleaned := strings.TrimPrefix(strings.TrimSuffix(tag, "##"), "@@")
+		parts := strings.Split(cleaned, "\t")
+		if len(parts) != 5 {
+			continue
+		}
+
+		// Parse page range
+		var pageNums []int
+		for _, p := range strings.Split(parts[0], "-") {
+			n, err := strconv.Atoi(p)
+			if err != nil {
+				slog.Warn("ExtractPositions: invalid page number in tag", "tag", tag, "part", p, "err", err)
+				continue
+			}
+			pageNums = append(pageNums, n-1) // 0-index
+		}
+
+		left, err := strconv.ParseFloat(parts[1], 64)
+		if err != nil {
+			slog.Warn("ExtractPositions: invalid left coordinate", "tag", tag, "err", err)
+			continue
+		}
+		right, err := strconv.ParseFloat(parts[2], 64)
+		if err != nil {
+			slog.Warn("ExtractPositions: invalid right coordinate", "tag", tag, "err", err)
+			continue
+		}
+		top, err := strconv.ParseFloat(parts[3], 64)
+		if err != nil {
+			slog.Warn("ExtractPositions: invalid top coordinate", "tag", tag, "err", err)
+			continue
+		}
+		bottom, err := strconv.ParseFloat(parts[4], 64)
+		if err != nil {
+			slog.Warn("ExtractPositions: invalid bottom coordinate", "tag", tag, "err", err)
+			continue
+		}
+
+		poss = append(poss, Position{
+			PageNumbers: pageNums,
+			Left:        left,
+			Right:       right,
+			Top:         top,
+			Bottom:      bottom,
+		})
+	}
+	return poss
+}
+
+// FormatPositionTag creates a @@ position tag string from page number and bounding box.
+//
+// Reverse of ExtractPositions. Used when converting PDF engine
+// bboxes back to RAGFlow position tag format.
+//
+// Example:
+//
+//	tag := FormatPositionTag(0, 50.0, 300.0, 200.0, 400.0)
+//	// "@@0-0\t50.0\t300.0\t200.0\t400.0##"
+func FormatPositionTag(pageNum int, left, right, top, bottom float64) string {
+	return fmt.Sprintf("@@%d\t%.1f\t%.1f\t%.1f\t%.1f##",
+		pageNum+1, left, right, top, bottom)
+}
+
+// FormatPositionTagRange creates a @@ position tag for multi-page content.
+//
+// Example:
+//
+//	tag := FormatPositionTagRange(0, 2, 50.0, 300.0, 200.0, 400.0)
+//	// "@@0-2\t50.0\t300.0\t200.0\t400.0##"
+func FormatPositionTagRange(fromPage, toPage int, left, right, top, bottom float64) string {
+	return fmt.Sprintf("@@%d-%d\t%.1f\t%.1f\t%.1f\t%.1f##",
+		fromPage+1, toPage+1, left, right, top, bottom)
+}