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.
Send a POST request with the HTML you want to convert in the Post body to the following url.
This will return a PDF of the HTML input.
POST /html2pdf?w=1024&h=768 HTTP/1.1 Host: localhost:8000 Content-Type: application/x-www-form-urlencoded Content-Length: 119
This is a test
This is a test
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. Be sure to use the --init switch to get rid of zombie processes of chromium.
Command Line Options
-host The host and port to listen of (refers to inside the container). Defaults to 0.0.0.0:8000 -debug Enables debug output. Default: false -ignore-cert-errors Also fetch ressources from origins with untrusted certificates or cert errors. -proxy Use a proxy server to connect to the internet. Please use format IP:PORT without a protocol. Example: 184.108.40.206:3128
Only build the webserver for non docker use
The following command builds the webserver for non docker use inside the
Only build docker image
To only build the docker image run
This will download the seccomp profile, all needed base images and builds the
gochro:dev tagged image.
Run the image
To run the image in interactive mode (docker output will be connected to current terminal) run
This will also build the image before running it. This maps the internal port 8000 to your machine.
Run the image in deamon mode
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.
Use the docker hub image
You can also use the prebuit image from dockerhub.
To pull the image run
docker pull firefart/gochro
Include in docker-compose
If 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 init: true container_name: gochro security_opt: - seccomp="chrome.json" command: -host 0.0.0.0:8000 networks: - gochronet networks: gochronet: driver: bridge