Issues with CefResourceHandler

[anlumo]

Hello,

I'm trying to implement my own custom scheme handler, but I'm running into problems. The process flow I have right now is:

Code: Select all

CefSchemeHandlerFactory::Create(browser, frame, "foo", request)
    return new FooResourceHandler
FooResourceHandler.Open(request, handle_request, callback)
    handle_request = true
    return true
FooResourceHandler.GetResponseHeaders(response, response_length, redirect_url)
    response.SetStatus(200)
    response.SetStatusText("OK")
    response.SetMimeType("text/html")
    response_length = 179
FooResourceHandler.Read(buffer, 65536 bytes to read, bytes_read, callback)
    copied 179 bytes into buffer
    bytes_read = 179
    return true
FooResourceHandler.Read(buffer, 65357 bytes to read, bytes_read, callback)
    bytes_read = 0
    return false
FooResourceHandler.Cancel()


Is there something wrong with this flow? Why is Read called twice, even though according to the documentation, the API should know that there's nothing left to read? Why is the operation canceled?

I've verified everything that I'm really setting the values as described above.

In case it's relevant, I'm using the C API, the pseudocode above is translated to the C++ naming scheme.

[Czarek]

The Read/Skip methods have a bug, I wrote about it in this comment: viewtopic.php?p=43543#p43543

[anlumo]

Ah, thank you! I'd never have connected the dots there on that post.

So, this sounds like the async API should work, right? The only issue is that the synchronous API doesn't call the async callbacks correctly.

[Czarek]

Try setting bytes_read, call callback->Continue(bytes_read) and return true.

Or use the old ReadResponse() method.

Best to report issue in the tracker.

[anlumo]

Still doesn't work. Now I have:

Code: Select all

CefSchemeHandlerFactory::Create(browser, frame, "foo", request)
    return new FooResourceHandler
FooResourceHandler.Open(request, handle_request, callback)
    handle_request = false
    return false
FooResourceHandler.ProcessRequest(request, callback)
    callback.Continue()
    return true
FooResourceHandler.GetResponseHeaders(response, response_length, redirect_url)
    response.SetStatus(200)
    response.SetStatusText("OK")
    response.SetMimeType("text/html")
    response_length = 179
FooResourceHandler.Cancel()


If I reenable my Read implementation, it gets called before the Cancel call, with the same behavior as in my initial post. I seems that I can't get the API to switch to the old flow. I do implement ReadResponse, but it's never called.

If I implement what you told me (calling Continue from Read and returning true), there's no change in behavior at all.

[Czarek]

People are coming back with the issue, but I don't see anyone taking time to report the issue in the tracker.

See also viewtopic.php?f=6&t=17072

[anlumo]

People are coming back with the issue, but I don't see anyone taking time to report the issue in the tracker.

Here: https://bitbucket.org/chromiumembedded/ ... chemes-non

[Czarek]

ReadResponse works fine in unit tests, so you must be doing something wrong. Make sure you override the method, check method signature and use the "override" keyword, see: https://github.com/chromiumembedded/cef ... st.cc#L323

[anlumo]

As I already mentioned, I'm using the C API, which doesn't have an override keyword. The compiler would also scream at me if the signature wouldn't match.

Maybe the bug is in the cpptoc wrapper?

[salvadordf]

I'm sorry to intrude but perhaps this could be relevant to this conversation.

The Delphi and Lazarus wrapper called CEF4Delphi also uses the C API and its CefResourceHandler demos work correctly with the ReadResponse method.