caddy/modules/caddyhttp/rewrite/caddyfile.go

297 lines
8.1 KiB
Go

// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package rewrite
import (
"encoding/json"
"strconv"
"strings"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig"
"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)
func init() {
httpcaddyfile.RegisterDirective("rewrite", parseCaddyfileRewrite)
httpcaddyfile.RegisterHandlerDirective("method", parseCaddyfileMethod)
httpcaddyfile.RegisterHandlerDirective("uri", parseCaddyfileURI)
httpcaddyfile.RegisterDirective("handle_path", parseCaddyfileHandlePath)
}
// parseCaddyfileRewrite sets up a basic rewrite handler from Caddyfile tokens. Syntax:
//
// rewrite [<matcher>] <to>
//
// Only URI components which are given in <to> will be set in the resulting URI.
// See the docs for the rewrite handler for more information.
func parseCaddyfileRewrite(h httpcaddyfile.Helper) ([]httpcaddyfile.ConfigValue, error) {
h.Next() // consume directive name
// count the tokens to determine what to do
argsCount := h.CountRemainingArgs()
if argsCount == 0 {
return nil, h.Errf("too few arguments; must have at least a rewrite URI")
}
if argsCount > 2 {
return nil, h.Errf("too many arguments; should only be a matcher and a URI")
}
// with only one arg, assume it's a rewrite URI with no matcher token
if argsCount == 1 {
if !h.NextArg() {
return nil, h.ArgErr()
}
return h.NewRoute(nil, Rewrite{URI: h.Val()}), nil
}
// parse the matcher token into a matcher set
userMatcherSet, err := h.ExtractMatcherSet()
if err != nil {
return nil, err
}
h.Next() // consume directive name again, matcher parsing does a reset
h.Next() // advance to the rewrite URI
return h.NewRoute(userMatcherSet, Rewrite{URI: h.Val()}), nil
}
// parseCaddyfileMethod sets up a basic method rewrite handler from Caddyfile tokens. Syntax:
//
// method [<matcher>] <method>
func parseCaddyfileMethod(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
h.Next() // consume directive name
if !h.NextArg() {
return nil, h.ArgErr()
}
if h.NextArg() {
return nil, h.ArgErr()
}
return Rewrite{Method: h.Val()}, nil
}
// parseCaddyfileURI sets up a handler for manipulating (but not "rewriting") the
// URI from Caddyfile tokens. Syntax:
//
// uri [<matcher>] strip_prefix|strip_suffix|replace|path_regexp <target> [<replacement> [<limit>]]
//
// If strip_prefix or strip_suffix are used, then <target> will be stripped
// only if it is the beginning or the end, respectively, of the URI path. If
// replace is used, then <target> will be replaced with <replacement> across
// the whole URI, up to <limit> times (or unlimited if unspecified). If
// path_regexp is used, then regular expression replacements will be performed
// on the path portion of the URI (and a limit cannot be set).
func parseCaddyfileURI(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
h.Next() // consume directive name
args := h.RemainingArgs()
if len(args) < 1 {
return nil, h.ArgErr()
}
var rewr Rewrite
switch args[0] {
case "strip_prefix":
if len(args) != 2 {
return nil, h.ArgErr()
}
rewr.StripPathPrefix = args[1]
if !strings.HasPrefix(rewr.StripPathPrefix, "/") {
rewr.StripPathPrefix = "/" + rewr.StripPathPrefix
}
case "strip_suffix":
if len(args) != 2 {
return nil, h.ArgErr()
}
rewr.StripPathSuffix = args[1]
case "replace":
var find, replace, lim string
switch len(args) {
case 4:
lim = args[3]
fallthrough
case 3:
find = args[1]
replace = args[2]
default:
return nil, h.ArgErr()
}
var limInt int
if lim != "" {
var err error
limInt, err = strconv.Atoi(lim)
if err != nil {
return nil, h.Errf("limit must be an integer; invalid: %v", err)
}
}
rewr.URISubstring = append(rewr.URISubstring, substrReplacer{
Find: find,
Replace: replace,
Limit: limInt,
})
case "path_regexp":
if len(args) != 3 {
return nil, h.ArgErr()
}
find, replace := args[1], args[2]
rewr.PathRegexp = append(rewr.PathRegexp, &regexReplacer{
Find: find,
Replace: replace,
})
case "query":
if len(args) > 4 {
return nil, h.ArgErr()
}
rewr.Query = &queryOps{}
var hasArgs bool
if len(args) > 1 {
hasArgs = true
err := applyQueryOps(h, rewr.Query, args[1:])
if err != nil {
return nil, err
}
}
for h.NextBlock(0) {
if hasArgs {
return nil, h.Err("Cannot specify uri query rewrites in both argument and block")
}
queryArgs := []string{h.Val()}
queryArgs = append(queryArgs, h.RemainingArgs()...)
err := applyQueryOps(h, rewr.Query, queryArgs)
if err != nil {
return nil, err
}
}
default:
return nil, h.Errf("unrecognized URI manipulation '%s'", args[0])
}
return rewr, nil
}
func applyQueryOps(h httpcaddyfile.Helper, qo *queryOps, args []string) error {
key := args[0]
switch {
case strings.HasPrefix(key, "-"):
if len(args) != 1 {
return h.ArgErr()
}
qo.Delete = append(qo.Delete, strings.TrimLeft(key, "-"))
case strings.HasPrefix(key, "+"):
if len(args) != 2 {
return h.ArgErr()
}
param := strings.TrimLeft(key, "+")
qo.Add = append(qo.Add, queryOpsArguments{Key: param, Val: args[1]})
case strings.Contains(key, ">"):
if len(args) != 1 {
return h.ArgErr()
}
renameValKey := strings.Split(key, ">")
qo.Rename = append(qo.Rename, queryOpsArguments{Key: renameValKey[0], Val: renameValKey[1]})
case len(args) == 3:
qo.Replace = append(qo.Replace, &queryOpsReplacement{Key: key, SearchRegexp: args[1], Replace: args[2]})
default:
if len(args) != 2 {
return h.ArgErr()
}
qo.Set = append(qo.Set, queryOpsArguments{Key: key, Val: args[1]})
}
return nil
}
// parseCaddyfileHandlePath parses the handle_path directive. Syntax:
//
// handle_path [<matcher>] {
// <directives...>
// }
//
// Only path matchers (with a `/` prefix) are supported as this is a shortcut
// for the handle directive with a strip_prefix rewrite.
func parseCaddyfileHandlePath(h httpcaddyfile.Helper) ([]httpcaddyfile.ConfigValue, error) {
h.Next() // consume directive name
// there must be a path matcher
if !h.NextArg() {
return nil, h.ArgErr()
}
// read the prefix to strip
path := h.Val()
if !strings.HasPrefix(path, "/") {
return nil, h.Errf("path matcher must begin with '/', got %s", path)
}
// we only want to strip what comes before the '/' if
// the user specified it (e.g. /api/* should only strip /api)
var stripPath string
if strings.HasSuffix(path, "/*") {
stripPath = path[:len(path)-2]
} else if strings.HasSuffix(path, "*") {
stripPath = path[:len(path)-1]
} else {
stripPath = path
}
// the ParseSegmentAsSubroute function expects the cursor
// to be at the token just before the block opening,
// so we need to rewind because we already read past it
h.Reset()
h.Next()
// parse the block contents as a subroute handler
handler, err := httpcaddyfile.ParseSegmentAsSubroute(h)
if err != nil {
return nil, err
}
subroute, ok := handler.(*caddyhttp.Subroute)
if !ok {
return nil, h.Errf("segment was not parsed as a subroute")
}
// make a matcher on the path and everything below it
pathMatcher := caddy.ModuleMap{
"path": h.JSON(caddyhttp.MatchPath{path}),
}
// build a route with a rewrite handler to strip the path prefix
route := caddyhttp.Route{
HandlersRaw: []json.RawMessage{
caddyconfig.JSONModuleObject(Rewrite{
StripPathPrefix: stripPath,
}, "handler", "rewrite", nil),
},
}
// prepend the route to the subroute
subroute.Routes = append([]caddyhttp.Route{route}, subroute.Routes...)
// build and return a route from the subroute
return h.NewRoute(pathMatcher, subroute), nil
}