From f1f7842dd2ed110e9958f56d79ec504ae5d2bcd6 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@archive.org>
Date: Sat, 16 May 2020 18:40:26 -0700
Subject: crude djvu XML parsing

---
 fatcat_scholar/djvu.py | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 fatcat_scholar/djvu.py

(limited to 'fatcat_scholar/djvu.py')

diff --git a/fatcat_scholar/djvu.py b/fatcat_scholar/djvu.py
new file mode 100644
index 0000000..b4a0774
--- /dev/null
+++ b/fatcat_scholar/djvu.py
@@ -0,0 +1,49 @@
+
+from io import StringIO
+from typing import List, Dict, Tuple, Optional, Any, Sequence
+import xml.etree.ElementTree as ET
+
+def djvu_extract_leaf_texts(blob: StringIO, only_leaves: Optional[List[int]] = None) -> Dict[int, str]:
+    """
+    Takes an in-memory djvu XML string (note: not an actual djvu file, just the
+    IA XML file type), and iterates throug
+    """
+
+    leaf_text = dict()
+    max_leaf = None
+    if only_leaves:
+        max_leaf = max(only_leaves)
+    elem_iter = ET.iterparse(blob, ["start", "end"])
+    for (event, element) in elem_iter:
+        if event == "start":
+            continue
+        if not (element.tag == "OBJECT" and event == "end"):
+            continue
+
+        # <OBJECT data="file://localhost//tmp/derive/ERIC_ED441501//ERIC_ED441501.djvu" height="6545" type="image/x.djvu" usemap="ERIC_ED441501_0002.djvu" width="5048">
+        usemap = element.get('usemap')
+        if not usemap:
+            continue
+        leaf_num = None
+        try:
+            leaf_num = int(usemap.replace('.djvu', '').split('_')[-1])
+        except:
+            continue
+        if only_leaves is not None and leaf_num is not None:
+            if leaf_num not in only_leaves:
+                continue
+            if max_leaf is not None and leaf_num > max_leaf:
+                break
+        paragraph_texts = []
+        for paragraph in element.iter("PARAGRAPH"):
+            tokens = [r.strip() for r in paragraph.itertext()]
+            tokens = [t for t in tokens if t]
+            p_text = " ".join(tokens)
+            if p_text:
+                paragraph_texts.append(p_text)
+        page_text = "\n".join(paragraph_texts)
+        #print(f"### {leaf_num}\n{page_text}\n")
+        if page_text:
+            leaf_text[leaf_num] = page_text
+        element.clear()
+    return leaf_text
-- 
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