CORS for Gin

gin-cors is a middleware written in Go (Golang) specifically for the Gin Framework that implements the Cross Origin Resource Sharing specification from the W3C. Implementing CORS headers enable pages within a modern web browser to consume resources (such as REST APIs) from servers that are on a different domain.

Getting Started

To use this library, add the following code into your Gin router setup:

import "github.com/itsjamie/gin-cors"

// Initialize a new Gin router
router := gin.New()

// Apply the middleware to the router (works with groups too)
router.Use(cors.Middleware(cors.Config{
	Origins:        "*",
	Methods:        "GET, PUT, POST, DELETE",
	RequestHeaders: "Origin, Authorization, Content-Type",
	ExposedHeaders: "",
	MaxAge: 50 * time.Second,
	Credentials: true,
	ValidateHeaders: false,
}))

Setup Options

The middleware can be configured with four options, which match the HTTP headers that it generates:

Parameter	Type	Details
Origins	string	A comma delimited list of origins which have access. For example: "http://localhost, http://api.server.com, http://files.server.com"
RequestHeaders	string	A comma delimited list of allowed HTTP that is passed to the browser in the Access-Control-Allow-Headers header.
ExposeHeaders	string	A comma delimited list of HTTP headers that should be exposed to the CORS client via the Access-Control-Expose-Headers header.
Methods	string	A comma delimited list of allowed HTTP methods that is passed to the browser in the Access-Control-Allow-Methods.
MaxAge	time.Duration	The amount of time a preflight request should be cached, if not specified, the header Access-Control-Max-Age will not be set.
Credentials	bool	This is passed in the Access-Control-Allow-Credentials header. If true Cookies, HTTP authentication and the client-side SSL certificates will be sent on previous interactions with the origin.
ValidateHeaders	bool	If false we skip validating the requested headers/methods with the list of allowed ones, and instead just respond with all what we support, it is up to the client implementating CORS to deny the request. This is an optimization allowed by the specification.

CORS Resources

• HTML Rocks Tutorial: Using CORS
• Mozilla Developer Network: CORS Reference
• CORS Specification from W3C

Special Thanks

Special thanks to benpate for providing a foundation to work from.

License

The code is licensed under the MIT License. See LICENSE file for more details.