wkhtmltopdf as a web service

A dockerized webservice written in Spring Boot / Java that uses wkhtmltopdf to convert HTML into documents (images or pdf files). Supports wkhtmltoimage as well for generation of .png and .jpg formats.

Usage

The service listens on port 3000 for POST requests on the root path (/). The body should contain a JSON-encoded object containing the following parameters:

• url: The URL of the page to convert starting with http:// or https://
• options: A list of key-value arguments that are passed on to the appropriate wkhtmltopdf binary. Boolean values are interpreted as flag arguments (e.g.: --greyscale). Repeatable options are nested. (see the examples and wkhtml docs for --allow","--bypass-proxy-for","--cookie","--custom-header","--post","--post-file","--run-script","--replace ).
• cmdline: An alternative form of presenting arguments in a string with comma separated arguments just as listed in the wkhtmltopdf docs except for the executable binary filename and the output [-] parameter.

The type of document to generate can be either jpg, png or pdf. Defauts to pdf if not specified. Depending on the output type the appropriate binary is called. Example: posting the following JSON:

{
  "url": "http://www.google.com",
  "options": {
    "--margin-bottom": "1cm",
    "--orientation": "Landscape",
    "--grayscale": true,
    "--cookie": {
        "foo": "bar",
        "baz": "foo"
    }
  }
}

will have the effect of the following command-line being executed on the server:

/usr/local/bin/wkhtmltopdf --margin-bottom 1cm --orientation Landscape --grayscale --cookie foo bar --cookie baz foo http://www.google.com -

and is just the same as:

{
  "url": "http://www.google.com",
  "cmdline" : "--margin-bottom, 1cm, --orientation, landscape, --grayscale, --cookie, foo, bar, --cookie, baz, foo"
}

See more Examples

The - at the end of the command-line is so that the document contents are redirected to stdout so we can in turn redirect it to the web server's response stream.

When using jpg or png output, the set of options you can pass are actually more limited. Please check wkhtmltopdf usage docs or rather just use wkhtmltopdf --help or wkhtmltoimage --help to get help on the available command-line arguments. Image output can be achieved with the --format: png or --format: jpg options.

Response status

The service returns these http status codes:

• 200: Ok with response content-type application/pdf (or image/jpeg or ìmage/png)
• 400: Bad request in case of json request parsing errors. Response body contains error information content-type text/html from the parser.
• 404: Not found if the service path is incorrect or
• 405: Not allowed if the service method is incorrect
• 500: Internal server error in case of wkhtmltopdf exits with return code other than 0. Response body contains the errorStream generated by wkhtmltopdf with content-type text/html.

Build instructions

Build instructions

Release history

0.0.3 Improved wkhtml error logging

TODO

Sorry - we have no testcases yet :(

License

This code is released under the Apache License.