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