gochro is a small docker image with chromium installed and a golang based webserver to interact wit it. It can be used to take screenshots of websites using chromium-headless and convert HTML pages to PDF.
If errors occur the error will be logged to stdout and a non information leaking error message is presented to the user.
This project is currently used on https://wpscan.io for taking website screenshots and to generate PDF reports.
This URL takes a Screenshot of https://firefart.at with a resolution of 1024x768 and returns an image.
http://localhost:8080/screenshot?url=https://firefart.at&w=1024&h=768
Send a POST request with the HTML you want to convert in the Post body to the following url.
http://localhost:8080/html2pdf?w=1024&h=768
This will return a PDF of the HTML input.
Example:
POST /html2pdf?w=1024&h=768 HTTP/1.1
Host: localhost:8000
Content-Type: application/x-www-form-urlencoded
Content-Length: 119
<html>
<head><title>Test Page</title></head>
<body>
<h1>This is a test</h1>
<p>This is a test</p>
</body>
</html>
To run this image you should use the seccomp profile provided by Jess Frazelle. The privileges on the host are needed for chromiums internal security sandbox. You can also deactivate the sandbox on chromium (would require changes in main.go) but that's a bad idea and puts your server at risk, so please use the seccomp profile instead.
I included all the necessary steps in the included Makefile to build and run everything
The following command builds the webserver for non docker use inside the build directory
make allTo only build the docker image run
make docker-updateThis will download the seccomp profile, all needed base images and builds the gochro:dev tagged image.
To run the image in interactive mode (docker output will be connected to current terminal) run
make docker-runThis will also build the image before running it. This maps the internal port 8000 to your machine.
To run it in deamon mode use the following command. This will launch everything in the background. Be aware that the webserver is rerun on startup of the machine if you don't shut down the container manually.
make docker-run-daemonYou can also use the prebuit image from dockerhub.
To pull the image run
docker pull firefart/gochroIf you want to include this image in a docker-compose file you can use the following example. Just connect the gochronet to the other service so the containers can communicate with each other.
Please note that the 0.0.0.0 in the command only applies to the network inside the docker container itself. If you want to access it from your local machine you need to add a port mapping.
version: '3.7'
services:
gochro:
image: firefart/gochro
container_name: gochro
security_opt:
- seccomp="chrome.json"
command: -host 0.0.0.0:8000
networks:
- gochronet
networks:
gochronet:
driver: bridge