88 lines
2.0 KiB
Go
88 lines
2.0 KiB
Go
// Copyright (C) 2017 Michał Matczuk
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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 proto
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import (
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"fmt"
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"net/http"
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)
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// Protocol HTTP headers.
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const (
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HeaderAction = "T-Action"
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HeaderError = "T-Error"
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HeaderForwardedBy = "T-Forwarded-By"
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HeaderForwardedFor = "T-Forwarded-For"
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HeaderPath = "T-Path"
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HeaderProtocol = "T-Proto"
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)
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// Known actions.
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const (
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ActionProxy string = "proxy"
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)
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// Known protocol types.
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const (
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HTTP = "http"
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TCP = "tcp"
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TCP4 = "tcp4"
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TCP6 = "tcp6"
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UNIX = "unix"
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WS = "ws"
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)
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// ControlMessage is sent from server to client before streaming data. It's
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// used to inform client about the data and action to take. Based on that client
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// routes requests to backend services.
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type ControlMessage struct {
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Action string
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Protocol string
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ForwardedFor string
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ForwardedBy string
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Path string
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}
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// ReadControlMessage reads ControlMessage from HTTP headers.
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func ReadControlMessage(h http.Header) (*ControlMessage, error) {
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msg := ControlMessage{
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Action: h.Get(HeaderAction),
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Protocol: h.Get(HeaderProtocol),
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ForwardedFor: h.Get(HeaderForwardedFor),
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ForwardedBy: h.Get(HeaderForwardedBy),
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Path: h.Get(HeaderPath),
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}
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var missing []string
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if msg.Action == "" {
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missing = append(missing, HeaderAction)
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}
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if msg.Protocol == "" {
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missing = append(missing, HeaderProtocol)
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}
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if msg.ForwardedFor == "" {
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missing = append(missing, HeaderForwardedFor)
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}
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if msg.ForwardedBy == "" {
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missing = append(missing, HeaderForwardedBy)
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}
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if len(missing) != 0 {
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return nil, fmt.Errorf("missing headers: %s", missing)
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}
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return &msg, nil
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}
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// Update writes ControlMessage to HTTP header.
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func (c *ControlMessage) Update(h http.Header) {
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h.Set(HeaderAction, string(c.Action))
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h.Set(HeaderProtocol, c.Protocol)
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h.Set(HeaderForwardedFor, c.ForwardedFor)
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h.Set(HeaderForwardedBy, c.ForwardedBy)
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h.Set(HeaderPath, c.Path)
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}
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