Added migration script for old cassettes

vcr/migration.py

@@ -0,0 +1,104 @@
+"""
+Migration script for old 'yaml' and 'json' cassettes
+
+.. warning:: Backup your cassettes files before migration.
+
+It merges and deletes the request obsolete keys (protocol, host, port, path)
+into new 'uri' key.
+Usage::
+
+    python -m vcr.migration PATH
+
+The PATH can be path to the directory with cassettes or cassette itself
+"""
+
+from contextlib import closing
+import json
+import os
+import re
+import shutil
+import sys
+import tempfile
+
+
+PARTS = [
+    'protocol',
+    'host',
+    'port',
+    'path',
+]
+
+
+def build_uri(**parts):
+    return "{protocol}://{host}:{port}{path}".format(**parts)
+
+
+def migrate_json(in_fp, out_fp):
+    data = json.load(in_fp)
+    for item in data:
+        req = item['request']
+        uri = {k: req.pop(k) for k in PARTS}
+        req['uri'] = build_uri(**uri)
+    json.dump(data, out_fp, indent=4)
+
+
+def migrate_yml(in_fp, out_fp):
+    migrated = False
+    uri = dict.fromkeys(PARTS, None)
+    for line in in_fp:
+        for part in uri:
+            match = re.match('\s+{}:\s(.*)'.format(part), line)
+            if match:
+                uri[part] = match.group(1)
+                break
+        else:
+            out_fp.write(line)
+
+        if None not in uri.values():  # if all uri parts are collected
+            out_fp.write("    uri: {}\n".format(build_uri(**uri)))
+            uri = dict.fromkeys(PARTS, None)  # reset dict
+            migrated = True
+    if not migrated:
+        raise RuntimeError("migration failed")
+
+
+def migrate(file_path, migration_fn):
+    # because we assume that original files can be reverted
+    # we will try to copy the content. (os.rename not needed)
+    with closing(tempfile.TemporaryFile()) as out_fp:
+        with open(file_path, 'r') as in_fp:
+            migration_fn(in_fp, out_fp)
+        with open(file_path, 'w') as in_fp:
+            out_fp.seek(0)
+            shutil.copyfileobj(out_fp, in_fp)
+
+
+def try_migrate(path):
+    try:  # try to migrate as json
+        migrate(path, migrate_json)
+    except:  # probably the file is not a json
+        try:  # let's try to migrate as yaml
+            migrate(path, migrate_yml)
+        except:  # oops probably the file is not a cassette
+            return False
+    return True
+
+
+def main():
+    if len(sys.argv) != 2:
+        raise SystemExit("Please provide path to cassettes directory or file. "
+                         "Usage: python -m vcr.migration PATH")
+
+    path = sys.argv[1]
+    if not os.path.isabs(path):
+        path = os.path.abspath(path)
+    for root, dirs, files in os.walk(path):
+        for file_name in files:
+            file_path = os.path.join(root, file_name)
+            migrated = try_migrate(file_path)
+            status = 'OK' if migrated else 'FAIL'
+            sys.stderr.write("[{}] {}\n".format(status, file_path))
+    sys.stderr.write("Done.\n")
+
+if __name__ == '__main__':
+    main()