CS50 Render

CS50 Render is a web app at render.cs50.io that allows you to render syntax-highlighted PDFs of source code, just as render50 allows at a command line. Here’s an example. Unlike render50, though, you can use CS50 Render without installing any dependencies on your own computer.

You can even render two or three files side by side for comparison’s sake. Here’s an example. When documenting cases of academic dishonesty in CS50, for instance, we render the cases’ files side by side and then annotate the PDFs for Harvard’s Honor Council.

PDFs can be annotated (for free) with:

API

CS50 Render supports, via POST using multipart/form-data, these HTTP parameters:

  • file, an input with type="file", the value of which is a file to be rendered.

  • size, the value of which, if provided, per developer.mozilla.org/en-US/docs/Web/CSS/@page/size, specifies the size of the page to render.

  • y, which, if provided (with any value), indicates that the files should be rendered side by side.

An HTTP request to CS50 Render must contain one or more values for file. But if y is present, the request must contain no more than three such values, as only two or three files can be rendered side by side.

A request can be submitted via HTML with:

<form action="https://render.cs50.io/" enctype="multipart/form-data" method="post">
    <input multiple name="file" type="file">
    <input name="y" type="checkbox">
    <input type="submit">
</form>

A request (with files like hello.c and hello.py) can be submitted via cURL with:

curl -F "file=@hello.c" -F "file=@hello.py" -o output.pdf https://render.cs50.io/

Or, in side-by-side mode, with:

curl -F "file=@hello.c" -F "file=@hello.py" -F "y=" -o output.pdf https://render.cs50.io/

A request (with files like hello.c and hello.py) can be submitted via Python with:

import requests

response = requests.post("https://render.cs50.io/", files=[("file", open("hello.c")), ("file", open("hello.py"))])
with open("output.pdf", "wb") as output:
    output.write(response.content)

Or, in side-by-side mode, with:

import requests

response = requests.post("https://render.cs50.io/", data={"y": True}, files=[("file", open("hello.c")), ("file", open("hello.py"))])
with open("output.pdf", "wb") as output:
    output.write(response.content)