func (p *ReverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
transport := p.Transport
if transport == nil {
transport = http.DefaultTransport
}
outreq := new(http.Request)
*outreq = *req // includes shallow copies of maps, but okay
p.Director(outreq)
outreq.Proto = "HTTP/1.1"
outreq.ProtoMajor = 1
outreq.ProtoMinor = 1
outreq.Close = false
// Remove hop-by-hop headers to the backend. Especially
// important is "Connection" because we want a persistent
// connection, regardless of what the client sent to us. This
// is modifying the same underlying map from req (shallow
// copied above) so we only copy it if necessary.
copiedHeaders := false
for _, h := range hopHeaders {
if outreq.Header.Get(h) != "" {
if !copiedHeaders {
outreq.Header = make(http.Header)
copyHeader(outreq.Header, req.Header)
copiedHeaders = true
}
outreq.Header.Del(h)
}
}
if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
// If we aren't the first proxy retain prior
// X-Forwarded-For information as a comma+space
// separated list and fold multiple headers into one.
if prior, ok := outreq.Header["X-Forwarded-For"]; ok {
clientIP = strings.Join(prior, ", ") + ", " + clientIP
}
outreq.Header.Set("X-Forwarded-For", clientIP)
}
res, err := transport.RoundTrip(outreq)
if err != nil {
p.logf("http: proxy error: %v", err)
rw.WriteHeader(http.StatusInternalServerError)
return
}
defer res.Body.Close()
for _, h := range hopHeaders {
res.Header.Del(h)
}
copyHeader(rw.Header(), res.Header)
rw.WriteHeader(res.StatusCode)
p.copyResponse(rw, res.Body)
}
// RequestFromMap creates an http.Request from CGI variables.
// The returned Request's Body field is not populated.
func RequestFromMap(params map[string]string) (*http.Request, error) {
r := new(http.Request)
r.Method = params["REQUEST_METHOD"]
if r.Method == "" {
return nil, errors.New("cgi: no REQUEST_METHOD in environment")
}
r.Proto = params["SERVER_PROTOCOL"]
var ok bool
r.ProtoMajor, r.ProtoMinor, ok = http.ParseHTTPVersion(r.Proto)
if !ok {
return nil, errors.New("cgi: invalid SERVER_PROTOCOL version")
}
r.Close = true
r.Trailer = http.Header{}
r.Header = http.Header{}
r.Host = params["HTTP_HOST"]
if lenstr := params["CONTENT_LENGTH"]; lenstr != "" {
clen, err := strconv.ParseInt(lenstr, 10, 64)
if err != nil {
return nil, errors.New("cgi: bad CONTENT_LENGTH in environment: " + lenstr)
}
r.ContentLength = clen
}
if ct := params["CONTENT_TYPE"]; ct != "" {
r.Header.Set("Content-Type", ct)
}
// Copy "HTTP_FOO_BAR" variables to "Foo-Bar" Headers
for k, v := range params {
if !strings.HasPrefix(k, "HTTP_") || k == "HTTP_HOST" {
continue
}
r.Header.Add(strings.Replace(k[5:], "_", "-", -1), v)
}
// TODO: cookies. parsing them isn't exported, though.
uriStr := params["REQUEST_URI"]
if uriStr == "" {
// Fallback to SCRIPT_NAME, PATH_INFO and QUERY_STRING.
uriStr = params["SCRIPT_NAME"] + params["PATH_INFO"]
s := params["QUERY_STRING"]
if s != "" {
uriStr += "?" + s
}
}
// There's apparently a de-facto standard for this.
// http://docstore.mik.ua/orelly/linux/cgi/ch03_02.htm#ch03-35636
if s := params["HTTPS"]; s == "on" || s == "ON" || s == "1" {
r.TLS = &tls.ConnectionState{HandshakeComplete: true}
}
if r.Host != "" {
// Hostname is provided, so we can reasonably construct a URL.
rawurl := r.Host + uriStr
if r.TLS == nil {
rawurl = "http://" + rawurl
} else {
rawurl = "https://" + rawurl
}
url, err := url.Parse(rawurl)
if err != nil {
return nil, errors.New("cgi: failed to parse host and REQUEST_URI into a URL: " + rawurl)
}
r.URL = url
}
// Fallback logic if we don't have a Host header or the URL
// failed to parse
if r.URL == nil {
url, err := url.Parse(uriStr)
if err != nil {
return nil, errors.New("cgi: failed to parse REQUEST_URI into a URL: " + uriStr)
}
r.URL = url
}
// Request.RemoteAddr has its port set by Go's standard http
// server, so we do here too. We don't have one, though, so we
// use a dummy one.
r.RemoteAddr = net.JoinHostPort(params["REMOTE_ADDR"], "0")
return r, nil
}