Any way to print PDF into memory, instead of to a file?

[danya02]

I'm making a web server that returns PDFs rendered from HTML templates. Right now I have to create a temporary file, pass its name to the PrintToPdfAsync method, and then read the contents into memory before sending them out to the user and deleting the file. I'd like to skip the step of going to the filesystem, and instead get the PDF bytes directly.

From what I can tell, it seems that CEF's printToPDF method returns a base64-encoded PDF bytes, or alternatively an experimental IO.StreamHandle. Could this be used for my goal?

[campersau]

You can try out the dev tools client. Here is an example for screenshots but the CDP printToPdf API you mentioned is also available:
https://github.com/cefsharp/CefSharp/wiki/General-Usage#screenshots

[danya02]

Thanks for the quick reply! I found that too, I was actually using the IBrowserHost method. I tried using the DevToolsClient, but it replies with:

CefSharp.DevTools.DevToolsClientException: DevTools Client Error :'Page.printToPDF' wasn't found

I think this issue is related: https://groups.google.com/a/chromium.org/g/chromium-extensions/c/gZ-jLD1bgCY

[amaitland]

What version are you using?

CefSharp.DevTools.DevToolsClientException: DevTools Client Error :'Page.printToPDF' wasn't found

Previously this was only supported in headless implementation, that should have been fixed in recent versions.

https://issues.chromium.org/issues/40533923

[danya02]

What version are you using?

    <TargetFramework>netcoreapp3.1</TargetFramework>
...
    <PackageReference Include="CefSharp.Common.NetCore" Version="125.0.210" />
    <PackageReference Include="CefSharp.OffScreen.NetCore" Version="125.0.210" />

only supported in headless implementation

That's what I'm trying to use, though. I can't use the headful browser on a web server anyway.

[amaitland]

OffScreen and headless are different things. CefSharp.OffScreen is technically a non-headless browser even though it renders to a bitmap.

Try switching to puppeteer sharp, you should be able to get the PDF in memory.