Local Cors Proxy Go

Description

Simple and fast (built on top of fasthttp proxy to bypass CORS issues during prototyping against existing APIs without having to worry about CORS

It was built to solve the issue of getting errors like this:

... has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

Limitations

Because func Do(req *Request, resp *Response) error is using for all type of queries it doesn't support redirects!

Usage

Let's imagine API endpoint that we want to request that has CORS issues:

https://licenseapi.herokuapp.com/licenses/mit

Pull Docker image and run a container:

docker pull lordotu/lcp-go

docker run -dti \
  -e LCP_GO_URL=https://licenseapi.herokuapp.com \
  -e LCP_GO_HOST=0.0.0.0 \
  -p 8118:8118 \
  --name lcp-go \
  lordotu/lcp-go

Then in your client code, new API endpoint:

http://localhost:8118/proxy/licenses/mit

End result will be a request to https://licenseapi.herokuapp.com/licenses/mit without the CORS issues!

Alternatively you can build binary (for Linux) from sources with command CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o lcp-go and run it like:

lcp-go --url https://licenseapi.herokuapp.com

Or:

LCP_GO_URL=https://licenseapi.herokuapp.com lcp-go

Configuring

You may set params via command line args or via env variables. All defaults are stored in .env file in the working directory.

Only one argument is required: --url (or LCP_GO_URL if you prefer env variables).

Options

Option	Shorthand	Example	Default
--url	-u	https://licenseapi.herokuapp.com
--port	-p	8119	8118
--host	-h	0.0.0.0	localhost
--urlSection	-s	through	proxy
--serverLogging	-l	true	false
--headers		{"X-Requested-With": "lcp-go"}	{}
--origin	-o	http://127.0.0.1	*
--reflectOrigin	-r	true	false

Environment variables

Option	Example	Default
LCP_GO_URL	https://licenseapi.herokuapp.com
LCP_GO_PORT	8119	8118
LCP_GO_HOST	0.0.0.0	localhost
LCP_GO_URL_SECTION	through	proxy
LCP_GO_SERVER_LOGGING	true	false
LCP_GO_HEADERS	{"X-Requested-With": "lcp-go"}	{}
LCP_GO_ORIGIN	http://127.0.0.1	*
LCP_GO_REFLECT_ORIGIN	true	false

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Inspired by: https://github.com/LordotU/corsyusha