69 lines
1.9 KiB
Go
69 lines
1.9 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package internal
|
|
|
|
import (
|
|
"net/http"
|
|
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
// HTTPClient is the context key to use with golang.org/x/net/context's
|
|
// WithValue function to associate an *http.Client value with a context.
|
|
var HTTPClient ContextKey
|
|
|
|
// ContextKey is just an empty struct. It exists so HTTPClient can be
|
|
// an immutable public variable with a unique type. It's immutable
|
|
// because nobody else can create a ContextKey, being unexported.
|
|
type ContextKey struct{}
|
|
|
|
// ContextClientFunc is a func which tries to return an *http.Client
|
|
// given a Context value. If it returns an error, the search stops
|
|
// with that error. If it returns (nil, nil), the search continues
|
|
// down the list of registered funcs.
|
|
type ContextClientFunc func(context.Context) (*http.Client, error)
|
|
|
|
var contextClientFuncs []ContextClientFunc
|
|
|
|
func RegisterContextClientFunc(fn ContextClientFunc) {
|
|
contextClientFuncs = append(contextClientFuncs, fn)
|
|
}
|
|
|
|
func ContextClient(ctx context.Context) (*http.Client, error) {
|
|
if ctx != nil {
|
|
if hc, ok := ctx.Value(HTTPClient).(*http.Client); ok {
|
|
return hc, nil
|
|
}
|
|
}
|
|
for _, fn := range contextClientFuncs {
|
|
c, err := fn(ctx)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if c != nil {
|
|
return c, nil
|
|
}
|
|
}
|
|
return http.DefaultClient, nil
|
|
}
|
|
|
|
func ContextTransport(ctx context.Context) http.RoundTripper {
|
|
hc, err := ContextClient(ctx)
|
|
// This is a rare error case (somebody using nil on App Engine).
|
|
if err != nil {
|
|
return ErrorTransport{err}
|
|
}
|
|
return hc.Transport
|
|
}
|
|
|
|
// ErrorTransport returns the specified error on RoundTrip.
|
|
// This RoundTripper should be used in rare error cases where
|
|
// error handling can be postponed to response handling time.
|
|
type ErrorTransport struct{ Err error }
|
|
|
|
func (t ErrorTransport) RoundTrip(*http.Request) (*http.Response, error) {
|
|
return nil, t.Err
|
|
}
|