docker/docker

package middleware // import "github.com/docker/docker/api/server/middleware"

import (
    "context"
    "net/http"

    "github.com/containerd/log"
    "github.com/docker/docker/api/types/registry"
)

// CORSMiddleware injects CORS headers to each request
// when it's configured.
type CORSMiddleware struct {
    defaultHeaders string
}

// NewCORSMiddleware creates a new CORSMiddleware with default headers.
func NewCORSMiddleware(d string) CORSMiddleware {
    return CORSMiddleware{defaultHeaders: d}
}

// WrapHandler returns a new handler function wrapping the previous one in the request chain.
func (c CORSMiddleware) WrapHandler(handler func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error) func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
    return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
        // If "api-cors-header" is not given, but "api-enable-cors" is true, we set cors to "*"
        // otherwise, all head values will be passed to HTTP handler
        corsHeaders := c.defaultHeaders
        if corsHeaders == "" {
            corsHeaders = "*"
        }

        log.G(ctx).Debugf("CORS header is enabled and set to: %s", corsHeaders)
        w.Header().Add("Access-Control-Allow-Origin", corsHeaders)
        w.Header().Add("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, "+registry.AuthHeader)
        w.Header().Add("Access-Control-Allow-Methods", "HEAD, GET, POST, DELETE, PUT, OPTIONS")
        return handler(ctx, w, r, vars)
    }
}