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caddy/middleware/fastcgi/fastcgi.go
2015-05-03 12:12:18 +01:00

321 lines
8.6 KiB
Go

// 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"
)
// New generates a new FastCGI middleware.
func New(c middleware.Controller) (middleware.Middleware, error) {
root, err := filepath.Abs(c.Root())
if err != nil {
return nil, err
}
rules, err := parse(c)
if err != nil {
return nil, err
}
return func(next middleware.Handler) middleware.Handler {
return Handler{
Next: next,
Rules: rules,
Root: root,
SoftwareName: "Caddy", // TODO: Once generators are not in the same pkg as handler, obtain this from some global const
SoftwareVersion: "", // TODO: Get this from some global const too
// TODO: Set ServerName and ServerPort to correct values... (as user defined in config)
}
}, nil
}
// Handler is a middleware type that can handle requests as a FastCGI client.
type Handler struct {
Next middleware.Handler
Root string // must be absolute path to site root
Rules []Rule
// 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 {
// 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.
path := r.URL.Path
// These criteria work well in this order for PHP sites
if middleware.Path(path).Matches(rule.Path) &&
(path[len(path)-1] == '/' ||
strings.HasSuffix(path, rule.Ext) ||
!h.exists(path)) {
if path[len(path)-1] == '/' && h.exists(path+rule.IndexFile) {
// If index file in specified folder exists, send request to it
path += rule.IndexFile
}
// Create environment for CGI script
env, err := h.buildEnv(r, rule, path)
if err != nil {
return http.StatusInternalServerError, err
}
// Connect to FastCGI gateway
fcgi, err := Dial("tcp", rule.Address)
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 "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
}
defer resp.Body.Close()
if err != nil && err != io.EOF {
return http.StatusBadGateway, err
}
// Write the response header
for key, vals := range resp.Header {
for _, val := range vals {
w.Header().Add(key, val)
}
}
w.WriteHeader(resp.StatusCode)
// 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 (h Handler) exists(path string) bool {
if _, err := os.Stat(h.Root + path); err == nil {
return true
}
return false
}
func (h Handler) buildEnv(r *http.Request, rule Rule, path string) (map[string]string, error) {
var env map[string]string
// Get absolute path of requested resource
absPath, err := filepath.Abs(h.Root + path)
if err != nil {
return env, err
}
// 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
splitPos := strings.Index(path, rule.SplitPath)
var docURI, scriptName, scriptFilename, pathInfo string
if splitPos == -1 {
// Request doesn't have the extension, so assume index file in root
docURI = "/" + rule.IndexFile
scriptName = "/" + rule.IndexFile
scriptFilename = h.Root + "/" + rule.IndexFile
pathInfo = path
} else {
// Request has the extension; path was split successfully
docURI = path[:splitPos+len(rule.SplitPath)]
pathInfo = path[splitPos+len(rule.SplitPath):]
scriptName = path
scriptFilename = absPath
}
// 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,
"PATH_TRANSLATED": h.Root + "/" + pathInfo, // Source for path_translated: http://www.oreilly.com/openbook/cgi/ch02_04.html
"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.Root,
"DOCUMENT_URI": docURI,
"HTTP_HOST": r.Host, // added here, since not always part of headers
"REQUEST_URI": r.URL.RequestURI(),
"SCRIPT_FILENAME": scriptFilename,
"SCRIPT_NAME": scriptName,
}
// 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
}
func parse(c middleware.Controller) ([]Rule, error) {
var rules []Rule
for c.Next() {
var rule Rule
args := c.RemainingArgs()
switch len(args) {
case 0:
return rules, c.ArgErr()
case 1:
rule.Path = "/"
rule.Address = args[0]
case 2:
rule.Path = args[0]
rule.Address = args[1]
case 3:
rule.Path = args[0]
rule.Address = args[1]
err := preset(args[2], &rule)
if err != nil {
return rules, c.Err("Invalid fastcgi rule preset '" + args[2] + "'")
}
}
for c.NextBlock() {
switch c.Val() {
case "ext":
if !c.NextArg() {
return rules, c.ArgErr()
}
rule.Ext = c.Val()
case "split":
if !c.NextArg() {
return rules, c.ArgErr()
}
rule.SplitPath = c.Val()
case "index":
if !c.NextArg() {
return rules, c.ArgErr()
}
rule.IndexFile = c.Val()
case "env":
envArgs := c.RemainingArgs()
if len(envArgs) < 2 {
return rules, c.ArgErr()
}
rule.EnvVars = append(rule.EnvVars, [2]string{envArgs[0], envArgs[1]})
}
}
rules = append(rules, rule)
}
return rules, nil
}
// preset configures rule according to name. It returns an error if
// name is not a recognized preset name.
func preset(name string, rule *Rule) error {
switch name {
case "php":
rule.Ext = ".php"
rule.SplitPath = ".php"
rule.IndexFile = "index.php"
default:
return errors.New(name + " is not a valid preset name")
}
return 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 does not indicate a file, an index file with this name will be assumed.
IndexFile string
// Environment Variables
EnvVars [][2]string
}
var headerNameReplacer = strings.NewReplacer(" ", "_", "-", "_")