feat: Adds Reader.from_manifest_data_and_stream()

for validating remote or sidecar manifests

Author: gpeacock

c2pa/c2pa_api/c2pa_api.py

@@ -36,9 +36,12 @@
 # reader = Reader("image/jpeg", open("test.jpg", "rb"))
 # json = reader.json()
 class Reader(api.Reader):
-    def __init__(self, format, stream):
+    def __init__(self, format, stream, manifest_data=None):
         super().__init__()
-        self.from_stream(format, C2paStream(stream))
+        if manifest_data is not None:
+            self.from_manifest_data_and_stream(format, manifest_data, stream)
+        else:
+            self.from_stream(format, C2paStream(stream))
 
     @classmethod
     def from_file(cls, path: str, format=None):

src/c2pa.udl

@@ -57,6 +57,9 @@ interface Reader {
   [Throws=Error]
   string from_stream([ByRef] string format, [ByRef] Stream reader);
 
+  [Throws=Error]
+  string from_manifest_data_and_stream([ByRef] bytes manifest_data, [ByRef] string format, [ByRef] Stream reader);
+
   [Throws=Error]
   string json();
 
@@ -79,6 +82,10 @@ interface Builder {
   [Throws=Error]
   void with_json([ByRef] string json);
 
+  void set_no_embed();
+
+  void set_remote_url([ByRef] string url)
+
   [Throws=Error]
   void add_resource([ByRef] string uri, [ByRef] Stream stream );
 

src/lib.rs

@@ -77,6 +77,19 @@ impl Reader {
         Ok(json)
     }
 
+    pub fn from_manifest_data_and_stream(&self, manifest_data: &[u8], format: &str, stream: &dyn Stream) -> Result<String> {
+        // uniffi doesn't allow mutable parameters, so we we use an adapter
+        let mut stream = StreamAdapter::from(stream);
+        let reader = c2pa::Reader::from_manifest_data_and_stream(manifest_data, format, &mut stream)?;
+        let json = reader.to_string();
+        if let Ok(mut st) = self.reader.try_write() {
+            *st = reader;
+        } else {
+            return Err(Error::RwLock);
+        };
+        Ok(json)
+    }
+
     pub fn json(&self) -> Result<String> {
         if let Ok(st) = self.reader.try_read() {
             Ok(st.json())
@@ -121,6 +134,25 @@ impl Builder {
         Ok(())
     }
 
+    /// Set to true to disable embedding a manifest 
+    pub fn set_no_embed(&self) -> Result<()> {
+        if let Ok(mut builder) = self.builder.try_write() {
+            builder.set_no_embed(true);
+        } else {
+            return Err(Error::RwLock);
+        };
+        Ok(())
+    }
+
+    pub fn set_remote_url(&self, remote_url: &str) -> Result<()> {
+        if let Ok(mut builder) = self.builder.try_write() {
+            builder.set_remote_url(remote_url);
+        } else {
+            return Err(Error::RwLock);
+        };
+        Ok(())
+    }
+
     /// Add a resource to the builder
     pub fn add_resource(&self, uri: &str, stream: &dyn Stream) -> Result<()> {
         if let Ok(mut builder) = self.builder.try_write() {

tests/unit_tests.py

@@ -44,6 +44,14 @@ def test_stream_read_and_parse(self):
             title = manifest = manifest_store["manifests"][manifest_store["active_manifest"]]["title"]
             self.assertEqual(title, "C.jpg")
 
+    def test_from_manifest_data_and_stream(self):
+        with open(testPath, "rb") as stream:
+            with open("tests/fixtures/manifest.c2pa", "r") as manifest_data:
+                reader = Reader("image/jpeg",stream, manifest_data)
+                manifest_store = json.loads(reader.json())
+                title = manifest = manifest_store["manifests"][manifest_store["active_manifest"]]["title"]
+                self.assertEqual(title, "C.jpg")
+
     def test_json_decode_err(self):
         with self.assertRaises(Error.Io):
             manifest_store = Reader("image/jpeg","foo")
@@ -92,7 +100,7 @@ def sign(data: bytes) -> bytes:
     # Create a local Ps256 signer with certs and a timestamp server
     signer = create_signer(sign, SigningAlg.PS256, certs, "http://timestamp.digicert.com")
 
-    def test_streams_build(self):
+    def test_streams_sign(self):
         with open(testPath, "rb") as file:
             builder = Builder(TestBuilder.manifestDefinition)
             output = io.BytesIO(bytearray())
@@ -101,7 +109,7 @@ def test_streams_build(self):
             reader = Reader("image/jpeg", output)
             self.assertIn("Python Test", reader.json())
 
-    def test_streams_build(self):
+    def test_archive_sign(self):
         with open(testPath, "rb") as file:
             builder = Builder(TestBuilder.manifestDefinition)
             archive = byte_array = io.BytesIO(bytearray())
@@ -113,5 +121,15 @@ def test_streams_build(self):
             reader = Reader("image/jpeg", output)
             self.assertIn("Python Test", reader.json())
 
+    def test_remote_sign(self):
+        with open(testPath, "rb") as file:
+            builder = Builder(TestBuilder.manifestDefinition)
+            builder.set_no_embed()
+            output = io.BytesIO(bytearray())
+            manifest_data = builder.sign(TestBuilder.signer, "image/jpeg", file, output)
+            output.seek(0)
+            reader = Reader.from_manifest_data_and_stream(manifest_data, "image/jpeg", output)
+            self.assertIn("Python Test", reader.json())
+
 if __name__ == '__main__':
     unittest.main()