Accept data: URIs on the command-line

Author: dlenski

test/test_all.py

@@ -187,3 +187,15 @@ def test_bad_file_format_error():
     global test_reader
     with helper.assertRaises(zxing.BarCodeReaderException):
         test_reader.decode(os.path.join(test_barcode_dir, 'bad_format.png'))
+
+
+def test_data_uris():
+    def _check_data_uri(uri, contents, suffix):
+        fobj = zxing.data_uri_to_fobj(uri)
+        assert fobj.getvalue() == contents
+        assert fobj.name.endswith(suffix)
+
+    yield from ((_check_data_uri, uri, contents, suffix) for (uri, contents, suffix) in (
+        ('data:image/png,ABCD', b'ABCD', '.png'),
+        ('data:image/jpeg;base64,3q2+7w==', bytes.fromhex('deadbeef'), '.jpeg'),
+    ))

zxing/__init__.py

@@ -14,8 +14,9 @@
 import sys
 import urllib.parse
 import zipfile
+from base64 import b64decode
 from enum import Enum
-from io import IOBase
+from io import BytesIO, IOBase
 from itertools import chain
 
 try:
@@ -34,6 +35,23 @@ def file_uri_to_path(s):
         raise ValueError(uri)
     return urllib.parse.unquote_plus(uri.path)
 
+
+def data_uri_to_fobj(s):
+    r = urllib.parse.urlparse(s)
+    if r.scheme == 'data' and not r.netloc:
+        mime, *rest = r.path.split(',', 1)
+        if rest:
+            if mime.endswith(';base64') and rest:
+                mime = mime[:-7]]
+                data = b64decode(rest[0])
+            else:
+                data = rest[0].encode()
+            ff = BytesIO(data)
+            ff.name = f'data_uri_{len(data)}_bytes.{mime.split("/")[-1]}'
+            return ff
+    raise ValueError("Cannot handle URIs other than data:MIMETYPE[;base64],DATA")
+
+
 class BarCodeReaderException(Exception):
     def __init__(self, message, filename=None):
         self.message, self.filename = message, filename

zxing/__main__.py

@@ -2,7 +2,7 @@
 import csv
 from sys import stdout, stdin
 
-from . import BarCodeReader, BarCodeReaderException
+from . import BarCodeReader, BarCodeReaderException, data_uri_to_fobj
 from .version import __version__
 
 
@@ -24,7 +24,7 @@ def main():
     p.add_argument('-c', '--csv', action='store_true')
     p.add_argument('--try-harder', action='store_true')
     p.add_argument('--pure-barcode', action='store_true')
-    p.add_argument('image', nargs='+')
+    p.add_argument('image', nargs='+', help='File path or data: URI of an image containing a barcode')
     p.add_argument('-P', '--classpath', help=argparse.SUPPRESS)
     p.add_argument('-J', '--java', help=argparse.SUPPRESS)
     p.add_argument('-V', '--version', action='store_true')
@@ -46,6 +46,12 @@ def main():
         if fn == '-':
             ff = stdin.buffer
             fn = ff.name
+        elif ':' in fn:
+            try:
+                ff = data_uri_to_fobj(fn)
+                fn = ff.name
+            except ValueError as exc:
+                p.error(exc.args[0])
         else:
             ff = fn