initial wayback-to-webcapture helper

1 files changed, 203 insertions, 0 deletions

diff --git a/extra/demo_entities/static_wayback.py b/extra/demo_entities/static_wayback.py
new file mode 100755
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+++ b/extra/demo_entities/static_wayback.py
@@ -0,0 +1,203 @@
+#!/usr/bin/env python3
+
+"""
+Helpers to create Web Capture entities from extracted wayback content.
+
+Works as a stand-alone script (for debugging) or as library routines.
+"""
+
+import sys
+import json
+import base64
+import hashlib
+import requests
+import datetime
+import argparse
+from bs4 import BeautifulSoup
+
+from fatcat_client import *
+
+CDX_API_BASE = "https://web.archive.org/cdx/search/cdx"
+GWB_URL_BASE = "https://web.archive.org/web"
+REQ_SESSION = requests.Session()
+
+
+def b32_hex(s):
+    """copy/pasta from elsewhere"""
+    s = s.strip().split()[0].lower()
+    if s.startswith("sha1:"):
+        s = s[5:]
+    if len(s) != 32:
+        return s
+    return base64.b16encode(base64.b32decode(s.upper())).lower().decode('utf-8')
+
+def parse_wbm_url(url):
+    """Takes a wayback machine URL, and returns a tuple:
+
+        (timestamp, datetime, original_url)
+    """
+    chunks = url.split('/')
+    assert len(chunks) >= 6
+    assert chunks[2] == 'web.archive.org'
+    assert chunks[3] == 'web'
+    return (chunks[4],
+            parse_wbm_timestamp(chunks[4]),
+            '/'.join(chunks[5:]))
+
+def test_parse_wbm_url():
+    u = "http://web.archive.org/web/20010712114837/http://www.dlib.org/dlib/june01/reich/06reich.html"
+    assert parse_wbm_url(u) == (
+        "20010712114837",
+        datetime.datetime(2001, 7, 12, 11, 48, 37),
+        "http://www.dlib.org/dlib/june01/reich/06reich.html")
+
+def parse_wbm_timestamp(timestamp):
+    """
+    Takes a complete WBM timestamp string (like "20020327115625") and returns a
+    python datetime object (UTC)
+    """
+    # strip any "im_" or "id_" suffix
+    if timestamp.endswith('_'):
+        timestamp = timestamp[:-3]
+    # inflexible; require the full second-precision timestamp
+    assert len(timestamp) == 14
+    return datetime.datetime(
+        year=int(timestamp[0:4]),
+        month=int(timestamp[4:6]),
+        day=int(timestamp[6:8]),
+        hour=int(timestamp[8:10]),
+        minute=int(timestamp[10:12]),
+        second=int(timestamp[12:14]))
+
+def test_parse_wbm_timestamp():
+    assert parse_wbm_timestamp("20010712114837") == \
+        datetime.datetime(2001, 7, 12, 11, 48, 37)
+
+def fetch_wbm(url):
+    resp = REQ_SESSION.get(url)
+    resp.raise_for_status()
+    assert resp.content
+    return resp.content
+
+def lookup_cdx(embed_url, verify_hashes=True, cdx_output=None):
+    assert embed_url.startswith('/web/')
+    embed_url = embed_url.split('/')
+    timestamp = embed_url[2]
+    if timestamp.endswith('_'):
+        timestamp = timestamp[:-3]
+    url = '/'.join(embed_url[3:])
+    #print((timestamp, url))
+    resp = REQ_SESSION.get(CDX_API_BASE, params=dict(
+        url=url,
+        closest=timestamp,
+        sort="closest",
+        resolveRevisits="true",
+        matchType="exact",
+        limit=1,
+    ))
+    resp.raise_for_status()
+    #print(resp.url)
+    if resp.content:
+        hit = resp.content.decode('utf-8').split('\n')[0]
+        if cdx_output:
+            cdx_output.write(hit + "\n")
+        cdx = hit.split(' ')
+        cdx = [x if (x and x != '-') else None for x in cdx]
+        webcapture_cdx = WebcaptureEntityCdx(
+            surt=cdx[0],
+            timestamp=parse_wbm_timestamp(cdx[1]),
+            url=cdx[2],
+            mimetype=cdx[3],
+            status_code=(cdx[4] and int(cdx[4])) or None,
+            sha1=b32_hex(cdx[5]),
+            sha256=None,
+        )
+        if verify_hashes:
+            resp = REQ_SESSION.get(GWB_URL_BASE + "/{}id_/{}".format(
+                cdx[1], # raw timestamp
+                webcapture_cdx.url))
+            resp.raise_for_status()
+            assert webcapture_cdx.sha1 == hashlib.sha1(resp.content).digest().hex()
+            webcapture_cdx.sha256 = hashlib.sha256(resp.content).digest().hex()
+        return webcapture_cdx
+    else:
+        return None
+
+def extract_embeds(soup):
+
+    embeds = set()
+
+    # <link href="">
+    for tag in soup.find_all('link', href=True):
+        if tag['href'].startswith('/web/'):
+            embeds.add(tag['href'])
+    # <img src="">
+    for tag in soup.find_all('img', src=True):
+        if tag['src'].startswith('/web/'):
+            embeds.add(tag['src'])
+    # <script src="">
+    for tag in soup.find_all('script', src=True):
+        if tag['src'].startswith('/web/'):
+            embeds.add(tag['src'])
+
+    return list(embeds)
+
+def static_wayback_webcapture(wayback_url, cdx_output=None):
+    """
+    Given a complete wayback machine capture URL, like:
+
+        http://web.archive.org/web/20010712114837/http://www.dlib.org/dlib/june01/reich/06reich.html
+
+    Will return a new ("bare") fatcat webcapture entity python object, with all
+    the CDX entries filled in.
+    """
+
+    wbm_html = fetch_wbm(wayback_url)
+    raw_timestamp, timestamp, original_url = parse_wbm_url(wayback_url)
+    #with open(rewritten_path, 'r') as fp:
+    #    soup = BeautifulSoup(fp, "lxml")
+    soup = BeautifulSoup(wbm_html, "lxml")
+    embeds = extract_embeds(soup)
+    cdx_obj = lookup_cdx("/web/{}/{}".format(raw_timestamp, original_url),
+        cdx_output=cdx_output)
+    cdx_list = [cdx_obj]
+    for url in embeds:
+        cdx_obj = lookup_cdx(url, cdx_output=cdx_output)
+        cdx_list.append(cdx_obj)
+    archive_urls = WebcaptureEntityArchiveUrls(
+        rel="wayback",
+        url="https://web.archive.org/web/",
+    )
+    wc = WebcaptureEntity(
+        cdx=cdx_list,
+        timestamp=timestamp,
+        original_url=original_url,
+        archive_urls=archive_urls,
+        release_ids=None)
+    return wc
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose',
+        action='store_true',
+        help="verbose output")
+    parser.add_argument('wayback_url',
+        type=str,
+        help="URL of wayback capture to extract from")
+    parser.add_argument('--json-output',
+        type=argparse.FileType('w'), default=sys.stdout,
+        help="where to write out webcapture entity (as JSON)")
+    parser.add_argument('--cdx-output',
+        type=argparse.FileType('w'), default=None,
+        help="(optional) file to write out CDX stub")
+
+    args = parser.parse_args()
+
+    # entity-to-JSON code; duplicate of entity_to_dict()
+    api_client = ApiClient()
+    wc = static_wayback_webcapture(args.wayback_url, cdx_output=args.cdx_output)
+    wc_dict = api_client.sanitize_for_serialization(wc)
+    print(json.dumps(wc_dict))
+
+if __name__ == '__main__':
+    main()