feat: Add CAWG validation to `Reader` #1370

scouten-adobe · 2025-09-02T22:54:36Z

This is a sketch of the changes I'd like to see made to the Reader interface to make CAWG more directly part of the reading process from clients' point of view.

…n't find it yet

…uten/cai-9212-add-cawg-to-reader

codecov · 2025-09-02T22:56:34Z

Codecov Report

❌ Patch coverage is 14.54545% with 47 lines in your changes missing coverage. Please review.
✅ Project coverage is 28.13%. Comparing base (c4fc7a6) to head (aeab1bc).

Files with missing lines	Patch %	Lines
sdk/src/manifest.rs	6.25%	30 Missing ⚠️
sdk/src/reader.rs	28.57%	15 Missing ⚠️
sdk/src/manifest_store_report.rs	0.00%	1 Missing ⚠️
sdk/src/validation_status.rs	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (c4fc7a6) and HEAD (aeab1bc). Click for more details.

HEAD has 2 uploads less than BASE

Flag BASE (c4fc7a6) HEAD (aeab1bc)

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Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1370       +/-   ##
===========================================
- Coverage   78.41%   28.13%   -50.29%     
===========================================
  Files         162      144       -18     
  Lines       39515    27439    -12076     
===========================================
- Hits        30986     7719    -23267     
- Misses       8529    19720    +11191

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tmathern · 2025-09-03T01:02:15Z

c2pa_c_ffi/src/c_api.rs


 // Run CAWG post-validation - this is async and requires a runtime.
 fn post_validate(result: Result<C2paReader, c2pa::Error>) -> Result<C2paReader, c2pa::Error> {
+    if true {


Will you need sync APIs here?

tmathern · 2025-09-03T01:03:11Z

sdk/examples/cawg_identity.rs

-        let mut reader = Reader::from_file(dest)?;
-
-        reader.post_validate_async(&CawgValidator {}).await?;
+        let reader = Reader::from_file_async(dest).await?;


Why not keep the sync interface too? I am not sure we can make everything async

tmathern · 2025-09-03T01:04:59Z

sdk/src/reader.rs

-        Self::from_store(store, &validation_log)
+        let /* mut */ result = Self::from_store(store, &validation_log)?;
+        if false {
+            // QUESTION: What to do if we're in the _sync version and there


Good question. I wouldn't want everything to become async. I wonder if we need the sync interface for some native bindings? It's not great but maybe we need a blocking API? Or a cawg validation opt-out for the sync path?

codspeed-hq · 2025-09-11T23:06:08Z

CodSpeed Performance Report

Merging #1370 will not alter performance

_{Comparing scouten/cai-9212-add-cawg-to-reader (aeab1bc) with main (c4fc7a6)}

Summary

✅ 16 untouched
⏩ 2 skipped¹

2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

…ed and where

scouten-adobe · 2025-09-12T21:51:36Z

I think I've solved the sync/async issues by leaving the existing approach in C API unchanged. I've added a new convenience function (async only) which does the combined test. That's what we were doing in the C API wrapper functions already and I've removed my changes to those functions.

scouten-adobe · 2025-09-12T22:04:50Z

sdk/src/reader.rs


    #[test]
    fn test_reader_post_validate() -> Result<()> {
+        if false {


Just noticed this was still here. Will remove shortly.

tmathern · 2025-09-12T22:07:23Z

sdk/src/reader.rs

+        format: &str,
+        stream: impl Read + Seek,
+    ) -> Result<Reader> {
+        let mut reader = Self::from_stream_async(format, stream).await?;


The implementations in
#[cfg(target_arch = "wasm32")]
pub async fn from_stream_with_cawg_async

and

#[cfg(not(target_arch = "wasm32"))]
pub async fn from_stream_with_cawg_async

are the same. Is there no way to reuse instead of duplicating? No trick to bypass the differences in requesteds traits on the stream ?

I wish … I wish …

Sadly, there is not such a trick. (I've looked.)

emensch · 2025-09-12T22:44:26Z

sdk/src/reader.rs

+        if get_settings_value::<bool>("verify.verify_after_reading")? {
+            reader.post_validate_async(&CawgValidator {}).await?;
+        }


So without verify.verify_after_reading, this will behave the same as Reader::from_stream_async?

Unless I'm mistaken, that feels a bit unintuitive to me. I'd think that calling from_stream_with_cawg_async would be "enough" from an end-user perspective to opt in to CAWG validation.

gpeacock

Why not just say that Reader::from_stream_async() supports cawg but reader_from_stream() doesn't yet. The same would go for Reader:from_file() I don't see why we should add new cawg specific methods here.
Eventually, hopefully the sync methods can support cawg too.

Another option is that we can configure the cawg support with a setting. So if you have cawg enabled we always do the cawg call and if you don't there's no extra overhead.

Maybe there's a separate (or the same) option that allows the sync methods to block on the async call. you can can disable the setting if you don't want that behavior.

gpeacock · 2025-09-02T23:07:07Z

sdk/src/reader.rs

-        Self::from_store(store, &validation_log)
+        let /* mut */ result = Self::from_store(store, &validation_log)?;
+        if false {
+            // QUESTION: What to do if we're in the _sync version and there


I think we need to support both sync and async identity validation if we are going to include it at this level in the API. If it is part of validation, it can't just be async validation.

gpeacock · 2025-09-02T23:09:51Z

c2pa_c_ffi/src/c_api.rs

 }

 // Run CAWG post-validation - this is async and requires a runtime.
 fn post_validate(result: Result<C2paReader, c2pa::Error>) -> Result<C2paReader, c2pa::Error> {


PostValidate could be useful for validating and formatting any 3rd party assertions we don't have in the SDK.
Ideally there would be some way to integrate this into the definition of an Assertion such that you would just need to add an assertion handler to the SDK, but that's a problem for tomorrow.

scouten-adobe · 2025-09-17T16:23:55Z

sdk/src/reader.rs

+    /// [CAWG identity]: https://cawg.io/identity
+    /// [from_stream_with_cawg_async()]: Self::from_stream_with_cawg_async
+    #[cfg(not(target_arch = "wasm32"))]
+    pub async fn from_stream_with_cawg_async(


TO DO: Delete this and fold back into the from_stream_async call. Add a note (depending on outcome) that says not supported on sync.

TO DO: If CAWG identity assertion is encountered, do the asynchronous blocking call in the sync implementation (borrow from the C bindings). Gavin may add a setting to disable if the blocking behavior is undesirable.

scouten-adobe · 2025-09-17T16:37:52Z

TO DO: Review c2patool usage.

scouten-adobe · 2025-09-17T16:40:29Z

TO DO: Check in to whether verify-on-sign does CAWG identity assertion verification and if it becomes async as a result.

scouten-adobe added 3 commits August 5, 2025 13:35

TDD: Test that expects a success code for identity assertion but does…

41d19ae

…n't find it yet

Sketch in proposed changes for CAWG validation in Reader interface

ac8acc1

Merge branch 'scouten/cai-9212-identity-assertion-in-reader' into sco…

61c2ced

…uten/cai-9212-add-cawg-to-reader

scouten-adobe requested a review from gpeacock September 2, 2025 22:54

scouten-adobe self-assigned this Sep 2, 2025

tmathern reviewed Sep 3, 2025

View reviewed changes

Merge branch 'main' into scouten/cai-9212-add-cawg-to-reader

adc1715

emensch mentioned this pull request Sep 9, 2025

Add c2pa-types + typed activeManifest and manifestStore APIs contentauth/c2pa-js#11

Merged

Merge branch 'main' into scouten/cai-9212-add-cawg-to-reader

650d954

scouten-adobe changed the title ~~Add CAWG validation to reader~~ feat: Add CAWG validation to reader Sep 11, 2025

Remove unused import

d8c04e3

scouten-adobe added 2 commits September 11, 2025 16:07

Getting back into this project; a little more clarity on what is need…

faf671b

…ed and where

Clean up test noise now that I know where I need to place updates

0f90e21

scouten-adobe changed the title ~~feat: Add CAWG validation to reader~~ feat: Add CAWG validation to Reader Sep 12, 2025

Hmmm … maybe this doesn't need to be so complicated

5270494

scouten-adobe force-pushed the scouten/cai-9212-add-cawg-to-reader branch from ba322ff to 5270494 Compare September 12, 2025 21:44

scouten-adobe marked this pull request as ready for review September 12, 2025 21:50

"Fix" WASI build errors

c7928b8

tmathern requested a review from emensch September 12, 2025 22:03

scouten-adobe commented Sep 12, 2025

View reviewed changes

tmathern approved these changes Sep 12, 2025

View reviewed changes

emensch reviewed Sep 12, 2025

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gpeacock requested changes Sep 12, 2025

View reviewed changes

scouten-adobe commented Sep 17, 2025

View reviewed changes

Merge branch 'main' into scouten/cai-9212-add-cawg-to-reader

ccb6038

gpeacock and others added 3 commits September 18, 2025 23:55

feat: cawg in native Reader

25d029f

Merge branch 'main' into scouten/cai-9212-add-cawg-to-reader

c87e7f5

Reader::from_stream_async should use Store::from_store_async

aeab1bc

feat: Add CAWG validation to Reader #1370

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Merging #1370 will not alter performance

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scouten-adobe commented Sep 12, 2025

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scouten-adobe commented Sep 17, 2025

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scouten-adobe commented Sep 17, 2025

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feat: Add CAWG validation to `Reader` #1370

feat: Add CAWG validation to `Reader` #1370

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