0
Fork 0
mirror of https://github.com/caddyserver/caddy.git synced 2024-12-23 22:27:38 -05:00
caddy/middleware/fastcgi/fastcgi.go
2015-10-31 02:24:37 +01:00

283 lines
8.2 KiB
Go
Executable file

// Package fastcgi has middleware that acts as a FastCGI client. Requests
// that get forwarded to FastCGI stop the middleware execution chain.
// The most common use for this package is to serve PHP websites via php-fpm.
package fastcgi
import (
"errors"
"io"
"net/http"
"os"
"path/filepath"
"strconv"
"strings"
"github.com/mholt/caddy/middleware"
)
// Handler is a middleware type that can handle requests as a FastCGI client.
type Handler struct {
Next middleware.Handler
Rules []Rule
Root string
AbsRoot string // same as root, but absolute path
FileSys http.FileSystem
// These are sent to CGI scripts in env variables
SoftwareName string
SoftwareVersion string
ServerName string
ServerPort string
}
// ServeHTTP satisfies the middleware.Handler interface.
func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
for _, rule := range h.Rules {
// First requirement: Base path must match
if !middleware.Path(r.URL.Path).Matches(rule.Path) {
continue
}
// In addition to matching the path, a request must meet some
// other criteria before being proxied as FastCGI. For example,
// we probably want to exclude static assets (CSS, JS, images...)
// but we also want to be flexible for the script we proxy to.
fpath := r.URL.Path
if idx, ok := middleware.IndexFile(h.FileSys, fpath, rule.IndexFiles); ok {
fpath = idx
// Index file present.
// If request path cannot be split, return error.
if !h.canSplit(fpath, rule) {
return http.StatusInternalServerError, ErrIndexMissingSplit
}
} else {
// No index file present.
// If request path cannot be split, ignore request.
if !h.canSplit(fpath, rule) {
continue
}
}
// These criteria work well in this order for PHP sites
if !h.exists(fpath) || fpath[len(fpath)-1] == '/' || strings.HasSuffix(fpath, rule.Ext) {
// Create environment for CGI script
env, err := h.buildEnv(r, rule, fpath)
if err != nil {
return http.StatusInternalServerError, err
}
// Connect to FastCGI gateway
fcgi, err := getClient(&rule)
if err != nil {
return http.StatusBadGateway, err
}
var resp *http.Response
contentLength, _ := strconv.Atoi(r.Header.Get("Content-Length"))
switch r.Method {
case "HEAD":
resp, err = fcgi.Head(env)
case "GET":
resp, err = fcgi.Get(env)
case "OPTIONS":
resp, err = fcgi.Options(env)
case "POST":
resp, err = fcgi.Post(env, r.Header.Get("Content-Type"), r.Body, contentLength)
case "PUT":
resp, err = fcgi.Put(env, r.Header.Get("Content-Type"), r.Body, contentLength)
case "PATCH":
resp, err = fcgi.Patch(env, r.Header.Get("Content-Type"), r.Body, contentLength)
case "DELETE":
resp, err = fcgi.Delete(env, r.Header.Get("Content-Type"), r.Body, contentLength)
default:
return http.StatusMethodNotAllowed, nil
}
if resp.Body != nil {
defer resp.Body.Close()
}
if err != nil && err != io.EOF {
return http.StatusBadGateway, err
}
writeHeader(w, resp)
// Write the response body
// TODO: If this has an error, the response will already be
// partly written. We should copy out of resp.Body into a buffer
// first, then write it to the response...
_, err = io.Copy(w, resp.Body)
if err != nil {
return http.StatusBadGateway, err
}
return 0, nil
}
}
return h.Next.ServeHTTP(w, r)
}
func getClient(r *Rule) (*FCGIClient, error) {
// check if unix socket or TCP
if trim := strings.HasPrefix(r.Address, "unix"); strings.HasPrefix(r.Address, "/") || trim {
if trim {
r.Address = r.Address[len("unix:"):]
}
return Dial("unix", r.Address)
}
return Dial("tcp", r.Address)
}
func writeHeader(w http.ResponseWriter, r *http.Response) {
for key, vals := range r.Header {
for _, val := range vals {
w.Header().Add(key, val)
}
}
w.WriteHeader(r.StatusCode)
}
func (h Handler) exists(path string) bool {
if _, err := os.Stat(h.Root + path); err == nil {
return true
}
return false
}
func (h Handler) canSplit(path string, rule Rule) bool {
return strings.Contains(path, rule.SplitPath)
}
// buildEnv returns a set of CGI environment variables for the request.
func (h Handler) buildEnv(r *http.Request, rule Rule, fpath string) (map[string]string, error) {
var env map[string]string
// Get absolute path of requested resource
absPath := filepath.Join(h.AbsRoot, fpath)
// Separate remote IP and port; more lenient than net.SplitHostPort
var ip, port string
if idx := strings.Index(r.RemoteAddr, ":"); idx > -1 {
ip = r.RemoteAddr[:idx]
port = r.RemoteAddr[idx+1:]
} else {
ip = r.RemoteAddr
}
// Split path in preparation for env variables.
// Previous h.canSplit checks ensure this can never be -1.
splitPos := strings.Index(fpath, rule.SplitPath)
// Request has the extension; path was split successfully
docURI := fpath[:splitPos+len(rule.SplitPath)]
pathInfo := fpath[splitPos+len(rule.SplitPath):]
scriptName := fpath
scriptFilename := absPath
// Strip PATH_INFO from SCRIPT_NAME
scriptName = strings.TrimSuffix(scriptName, pathInfo)
// Get the request URI. The request URI might be as it came in over the wire,
// or it might have been rewritten internally by the rewrite middleware (see issue #256).
// If it was rewritten, there will be a header indicating the original URL,
// which is needed to get the correct RequestURI value for PHP apps.
const internalRewriteFieldName = "Caddy-Rewrite-Original-URI"
reqURI := r.URL.RequestURI()
if origURI := r.Header.Get(internalRewriteFieldName); origURI != "" {
reqURI = origURI
r.Header.Del(internalRewriteFieldName)
}
// Some variables are unused but cleared explicitly to prevent
// the parent environment from interfering.
env = map[string]string{
// Variables defined in CGI 1.1 spec
"AUTH_TYPE": "", // Not used
"CONTENT_LENGTH": r.Header.Get("Content-Length"),
"CONTENT_TYPE": r.Header.Get("Content-Type"),
"GATEWAY_INTERFACE": "CGI/1.1",
"PATH_INFO": pathInfo,
"QUERY_STRING": r.URL.RawQuery,
"REMOTE_ADDR": ip,
"REMOTE_HOST": ip, // For speed, remote host lookups disabled
"REMOTE_PORT": port,
"REMOTE_IDENT": "", // Not used
"REMOTE_USER": "", // Not used
"REQUEST_METHOD": r.Method,
"SERVER_NAME": h.ServerName,
"SERVER_PORT": h.ServerPort,
"SERVER_PROTOCOL": r.Proto,
"SERVER_SOFTWARE": h.SoftwareName + "/" + h.SoftwareVersion,
// Other variables
"DOCUMENT_ROOT": h.AbsRoot,
"DOCUMENT_URI": docURI,
"HTTP_HOST": r.Host, // added here, since not always part of headers
"REQUEST_URI": reqURI,
"SCRIPT_FILENAME": scriptFilename,
"SCRIPT_NAME": scriptName,
}
// compliance with the CGI specification that PATH_TRANSLATED
// should only exist if PATH_INFO is defined.
// Info: https://www.ietf.org/rfc/rfc3875 Page 14
if env["PATH_INFO"] != "" {
env["PATH_TRANSLATED"] = filepath.Join(h.AbsRoot, pathInfo) // Info: http://www.oreilly.com/openbook/cgi/ch02_04.html
}
// Some web apps rely on knowing HTTPS or not
if r.TLS != nil {
env["HTTPS"] = "on"
}
// Add env variables from config
for _, envVar := range rule.EnvVars {
env[envVar[0]] = envVar[1]
}
// Add all HTTP headers to env variables
for field, val := range r.Header {
header := strings.ToUpper(field)
header = headerNameReplacer.Replace(header)
env["HTTP_"+header] = strings.Join(val, ", ")
}
return env, nil
}
// Rule represents a FastCGI handling rule.
type Rule struct {
// The base path to match. Required.
Path string
// The address of the FastCGI server. Required.
Address string
// Always process files with this extension with fastcgi.
Ext string
// The path in the URL will be split into two, with the first piece ending
// with the value of SplitPath. The first piece will be assumed as the
// actual resource (CGI script) name, and the second piece will be set to
// PATH_INFO for the CGI script to use.
SplitPath string
// If the URL ends with '/' (which indicates a directory), these index
// files will be tried instead.
IndexFiles []string
// Environment Variables
EnvVars [][2]string
}
var (
headerNameReplacer = strings.NewReplacer(" ", "_", "-", "_")
ErrIndexMissingSplit = errors.New("configured index file(s) must include split value")
)