contrib: Add WARC merging script

Very useful for distributed, recursive crawls which create one WARC per
page.

1 files changed, 70 insertions, 0 deletions

diff --git a/contrib/mergeWarc.py b/contrib/mergeWarc.py
new file mode 100755
index 0000000..9442010
--- /dev/null
+++ b/contrib/mergeWarc.py
@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2018 crocoite contributors
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+"""
+Merge multiple WARC files into a single file, writing revisit records for items
+which occur multiple times
+"""
+
+import shutil, sys, re, os, logging
+from warcio.archiveiterator import ArchiveIterator
+from warcio.warcwriter import WARCWriter
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser(description='Merge WARCs, reads filenames from stdin.')
+    parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument('output', type=argparse.FileType ('wb'), help='Output WARC')
+
+    args = parser.parse_args()
+    loglevel = logging.DEBUG if args.verbose else logging.INFO
+    logging.basicConfig (level=loglevel)
+
+    unique = 0
+    revisit = 0
+    payloadMap = {}
+    writer = WARCWriter (args.output, gzip=True)
+    for l in sys.stdin:
+        l = l.strip ()
+        with open (l, 'rb') as fd:
+            for record in ArchiveIterator (fd):
+                if record.rec_type in {'resource', 'response'}:
+                    headers = record.rec_headers
+                    rid = headers.get_header('WARC-Record-ID')
+                    csum = headers.get_header('WARC-Payload-Digest')
+                    dup = payloadMap.get (csum, None)
+                    if dup is None:
+                        payloadMap[csum] = {'uri': headers.get_header('WARC-Target-URI'),
+                                'id': rid, 'date': headers.get_header('WARC-Date')}
+                        unique += 1
+                    else:
+                        logging.debug ('Record {} is duplicate of {}'.format (rid, dup['id']))
+                        record = writer.create_revisit_record (dup['uri'], csum, dup['uri'], dup['date'])
+                        record.rec_headers.add_header ('WARC-Truncated', 'length')
+                        record.rec_headers.add_header ('WARC-Refers-To', dup['id'])
+                        revisit += 1
+                else:
+                    unique += 1
+                writer.write_record (record)
+    logging.info ('Wrote {} unique records, {} revisits'.format (unique, revisit))
+