/
handler.go
231 lines (193 loc) · 5.56 KB
/
handler.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
package http
import (
"errors"
"fmt"
"io"
"net/http"
"strconv"
"strings"
context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/golang.org/x/net/context"
cmds "github.com/jbenet/go-ipfs/commands"
u "github.com/jbenet/go-ipfs/util"
)
var log = u.Logger("commands/http")
type Handler struct {
ctx cmds.Context
root *cmds.Command
origin string
}
var ErrNotFound = errors.New("404 page not found")
const (
streamHeader = "X-Stream-Output"
channelHeader = "X-Chunked-Output"
contentTypeHeader = "Content-Type"
contentLengthHeader = "Content-Length"
transferEncodingHeader = "Transfer-Encoding"
applicationJson = "application/json"
)
var mimeTypes = map[string]string{
cmds.JSON: "application/json",
cmds.XML: "application/xml",
cmds.Text: "text/plain",
}
func NewHandler(ctx cmds.Context, root *cmds.Command, origin string) *Handler {
// allow whitelisted origins (so we can make API requests from the browser)
if len(origin) > 0 {
log.Info("Allowing API requests from origin: " + origin)
}
return &Handler{ctx, root, origin}
}
func (i Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// create a context.Context to pass into the commands.
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
i.ctx.Context = ctx
log.Debug("Incoming API request: ", r.URL)
// error on external referers (to prevent CSRF attacks)
referer := r.Referer()
scheme := r.URL.Scheme
if len(scheme) == 0 {
scheme = "http"
}
host := fmt.Sprintf("%s://%s/", scheme, r.Host)
// empty string means the user isn't following a link (they are directly typing in the url)
if referer != "" && !strings.HasPrefix(referer, host) {
w.WriteHeader(http.StatusForbidden)
w.Write([]byte("403 - Forbidden"))
return
}
if len(i.origin) > 0 {
w.Header().Set("Access-Control-Allow-Origin", i.origin)
}
w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
req, err := Parse(r, i.root)
if err != nil {
if err == ErrNotFound {
w.WriteHeader(http.StatusNotFound)
} else {
w.WriteHeader(http.StatusBadRequest)
}
w.Write([]byte(err.Error()))
return
}
req.SetContext(i.ctx)
// call the command
res := i.root.Call(req)
// set the Content-Type based on res output
if _, ok := res.Output().(io.Reader); ok {
// we don't set the Content-Type for streams, so that browsers can MIME-sniff the type themselves
// we set this header so clients have a way to know this is an output stream
// (not marshalled command output)
// TODO: set a specific Content-Type if the command response needs it to be a certain type
w.Header().Set(streamHeader, "1")
} else {
enc, found, err := req.Option(cmds.EncShort).String()
if err != nil || !found {
w.WriteHeader(http.StatusInternalServerError)
return
}
mime := mimeTypes[enc]
w.Header().Set(contentTypeHeader, mime)
}
// set the Content-Length from the response length
if res.Length() > 0 {
w.Header().Set(contentLengthHeader, strconv.FormatUint(res.Length(), 10))
}
// if response contains an error, write an HTTP error status code
if e := res.Error(); e != nil {
if e.Code == cmds.ErrClient {
w.WriteHeader(http.StatusBadRequest)
} else {
w.WriteHeader(http.StatusInternalServerError)
}
}
out, err := res.Reader()
if err != nil {
w.Header().Set(contentTypeHeader, "text/plain")
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(err.Error()))
return
}
// if output is a channel and user requested streaming channels,
// use chunk copier for the output
_, isChan := res.Output().(chan interface{})
if !isChan {
_, isChan = res.Output().(<-chan interface{})
}
streamChans, _, _ := req.Option("stream-channels").Bool()
if isChan && streamChans {
// w.WriteString(transferEncodingHeader + ": chunked\r\n")
// w.Header().Set(channelHeader, "1")
// w.WriteHeader(200)
err = copyChunks(applicationJson, w, out)
if err != nil {
log.Debug(err)
}
return
}
flushCopy(w, out)
}
// flushCopy Copies from an io.Reader to a http.ResponseWriter.
// Flushes chunks over HTTP stream as they are read (if supported by transport).
func flushCopy(w http.ResponseWriter, out io.Reader) error {
if _, ok := w.(http.Flusher); !ok {
return copyChunks("", w, out)
}
io.Copy(&flushResponse{w}, out)
return nil
}
// Copies from an io.Reader to a http.ResponseWriter.
// Flushes chunks over HTTP stream as they are read (if supported by transport).
func copyChunks(contentType string, w http.ResponseWriter, out io.Reader) error {
hijacker, ok := w.(http.Hijacker)
if !ok {
return errors.New("Could not create hijacker")
}
conn, writer, err := hijacker.Hijack()
if err != nil {
return err
}
defer conn.Close()
writer.WriteString("HTTP/1.1 200 OK\r\n")
if contentType != "" {
writer.WriteString(contentTypeHeader + ": " + contentType + "\r\n")
}
writer.WriteString(transferEncodingHeader + ": chunked\r\n")
writer.WriteString(channelHeader + ": 1\r\n\r\n")
buf := make([]byte, 32*1024)
for {
n, err := out.Read(buf)
if n > 0 {
length := fmt.Sprintf("%x\r\n", n)
writer.WriteString(length)
_, err := writer.Write(buf[0:n])
if err != nil {
return err
}
writer.WriteString("\r\n")
writer.Flush()
}
if err != nil && err != io.EOF {
return err
}
if err == io.EOF {
break
}
}
writer.WriteString("0\r\n\r\n")
writer.Flush()
return nil
}
type flushResponse struct {
W http.ResponseWriter
}
func (fr *flushResponse) Write(buf []byte) (int, error) {
n, err := fr.W.Write(buf)
if err != nil {
return n, err
}
if flusher, ok := fr.W.(http.Flusher); ok {
flusher.Flush()
}
return n, err
}