Feature - accept content to render pdf by url

[usingtechnology]

Add ability to pass in the url argument to weasyprint.
Can set some of the additional url arguments, see class weasyprint.HTML(input, **kwargs)

[WadeBarnes]

Please update the documentation to identify and describe the new functionality. It would be nice if you could add an additional working example like the existing one.

[WadeBarnes]

@parc-jason, The API docs should be updated too;

[WadeBarnes]

Running curl -v -X POST -H 'Content-Type: text/plain' -d 'https://www.google.ca/?client=safari&channel=iphone_bm' -JLO http://127.0.0.1:5001/pdf?filename=result_from_url.pdf&type=url after building and starting the new image results in a PDF with just the URL printed:

Logs:

[2020-05-22 14:09:06,876] INFO in app: POST  /pdf?filename=result_from_url.pdf&type=url
2020-05-22 14:09:06,876 INFO: POST  /pdf?filename=result_from_url.pdf&type=url [in /app/app.py:51]
[2020-05-22 14:09:07,698] INFO in app:  ==> POST  /pdf?filename=result_from_url.pdf  ok
2020-05-22 14:09:07,698 INFO:  ==> POST  /pdf?filename=result_from_url.pdf  ok [in /app/app.py:64]

[WadeBarnes]

Suggested change

	curl -v -X POST -H 'Content-Type: text/plain' -d 'https://www.google.ca/?client=safari&channel=iphone_bm'-JLO http://127.0.0.1:5001/pdf?filename=result_from_url.pdf&type=url
	curl -v -X POST -H 'Content-Type: text/plain' -d 'https://www.google.ca/?client=safari&channel=iphone_bm' -JLO http://127.0.0.1:5001/pdf?filename=result_from_url.pdf&type=url

[WadeBarnes]

Did the following to build and run locally;

Wade@Epoch MINGW64 /c/docker-weasyprint (feature/weasyprint-by-url-arg)
$ docker build -t bcgovimages/weasyprint .
...

Wade@Epoch MINGW64 /c/docker-weasyprint (feature/weasyprint-by-url-arg)
$ docker run -p 5001:5001 bcgovimages/weasyprint