2019-08-09 13:05:47 -05:00
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// Copyright 2015 Matthew Holt and The Caddy Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package caddyhttp
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import (
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http: Change routes to sequential matcher evaluation (#2967)
Previously, all matchers in a route would be evaluated before any
handlers were executed, and a composite route of the matching routes
would be created. This made rewrites especially tricky, since the only
way to defer later matchers' evaluation was to wrap them in a subroute,
or to invoke a "rehandle" which often caused bugs.
Instead, this new sequential design evaluates each route's matchers then
its handlers in lock-step; matcher-handlers-matcher-handlers...
If the first matching route consists of a rewrite, then the second route
will be evaluated against the rewritten request, rather than the original
one, and so on.
This should do away with any need for rehandling.
I've also taken this opportunity to avoid adding new values to the
request context in the handler chain, as this creates a copy of the
Request struct, which may possibly lead to bugs like it has in the past
(see PR #1542, PR #1481, and maybe issue #2463). We now add all the
expected context values in the top-level handler at the server, then
any new values can be added to the variable table via the VarsCtxKey
context key, or just the GetVar/SetVar functions. In particular, we are
using this facility to convey dial information in the reverse proxy.
Had to be careful in one place as the middleware compilation logic has
changed, and moved a bit. We no longer compile a middleware chain per-
request; instead, we can compile it at provision-time, and defer only the
evaluation of matchers to request-time, which should slightly improve
performance. Doing this, however, we take advantage of multiple function
closures, and we also changed the use of HandlerFunc (function pointer)
to Handler (interface)... this led to a situation where, if we aren't
careful, allows one request routed a certain way to permanently change
the "next" handler for all/most other requests! We avoid this by making
a copy of the interface value (which is a lightweight pointer copy) and
using exclusively that within our wrapped handlers. This way, the
original stack frame is preserved in a "read-only" fashion. The comments
in the code describe this phenomenon.
This may very well be a breaking change for some configurations, however
I do not expect it to impact many people. I will make it clear in the
release notes that this change has occurred.
2020-01-09 12:00:13 -05:00
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"context"
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"fmt"
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"net/http"
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"strings"
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"github.com/caddyserver/caddy/v2"
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2020-09-25 18:50:26 -05:00
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"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
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2019-08-09 13:05:47 -05:00
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)
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func init() {
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2019-08-21 11:46:35 -05:00
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caddy.RegisterModule(VarsMiddleware{})
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caddy.RegisterModule(VarsMatcher{})
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caddy.RegisterModule(MatchVarsRE{})
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}
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2021-09-24 19:31:01 -05:00
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// VarsMiddleware is an HTTP middleware which sets variables to
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// have values that can be used in the HTTP request handler
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// chain. The primary way to access variables is with placeholders,
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// which have the form: `{http.vars.variable_name}`, or with
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// the `vars` and `vars_regexp` request matchers.
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//
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// The key is the variable name, and the value is the value of the
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// variable. Both the name and value may use or contain placeholders.
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type VarsMiddleware map[string]any
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// CaddyModule returns the Caddy module information.
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func (VarsMiddleware) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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ID: "http.handlers.vars",
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New: func() caddy.Module { return new(VarsMiddleware) },
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}
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}
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func (m VarsMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
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vars := r.Context().Value(VarsCtxKey).(map[string]any)
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repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
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for k, v := range m {
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keyExpanded := repl.ReplaceAll(k, "")
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if valStr, ok := v.(string); ok {
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v = repl.ReplaceAll(valStr, "")
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}
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vars[keyExpanded] = v
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}
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return next.ServeHTTP(w, r)
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}
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// UnmarshalCaddyfile implements caddyfile.Unmarshaler. Syntax:
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//
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// vars [<name> <val>] {
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// <name> <val>
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// ...
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// }
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func (m *VarsMiddleware) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
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d.Next() // consume directive name
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if *m == nil {
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*m = make(VarsMiddleware)
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}
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nextVar := func(headerLine bool) error {
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if headerLine {
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// header line is optional
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if !d.NextArg() {
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return nil
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}
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}
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varName := d.Val()
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if !d.NextArg() {
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return d.ArgErr()
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}
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varValue := d.ScalarVal()
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(*m)[varName] = varValue
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if d.NextArg() {
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return d.ArgErr()
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}
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return nil
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}
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2024-01-23 19:36:59 -05:00
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if err := nextVar(true); err != nil {
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return err
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}
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for d.NextBlock(0) {
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if err := nextVar(false); err != nil {
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return err
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}
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}
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return nil
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}
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2019-08-09 13:05:47 -05:00
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// VarsMatcher is an HTTP request matcher which can match
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// requests based on variables in the context or placeholder
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// values. The key is the placeholder or name of the variable,
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// and the values are possible values the variable can be in
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// order to match (logical OR'ed).
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//
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// If the key is surrounded by `{ }` it is assumed to be a
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// placeholder. Otherwise, it will be considered a variable
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// name.
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//
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// Placeholders in the keys are not expanded, but
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// placeholders in the values are.
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type VarsMatcher map[string][]string
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// CaddyModule returns the Caddy module information.
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func (VarsMatcher) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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ID: "http.matchers.vars",
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New: func() caddy.Module { return new(VarsMatcher) },
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}
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}
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2020-09-25 18:50:26 -05:00
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// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
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func (m *VarsMatcher) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
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if *m == nil {
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*m = make(map[string][]string)
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}
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// iterate to merge multiple matchers into one
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for d.Next() {
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var field string
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if !d.Args(&field) {
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return d.Errf("malformed vars matcher: expected field name")
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}
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vals := d.RemainingArgs()
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if len(vals) == 0 {
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return d.Errf("malformed vars matcher: expected at least one value to match against")
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}
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(*m)[field] = append((*m)[field], vals...)
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if d.NextBlock(0) {
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return d.Err("malformed vars matcher: blocks are not supported")
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}
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}
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return nil
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}
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// Match matches a request based on variables in the context,
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// or placeholders if the key is not a variable.
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func (m VarsMatcher) Match(r *http.Request) bool {
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if len(m) == 0 {
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return true
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}
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2022-08-02 15:39:09 -05:00
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vars := r.Context().Value(VarsCtxKey).(map[string]any)
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repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
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for key, vals := range m {
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var varValue any
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if strings.HasPrefix(key, "{") &&
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strings.HasSuffix(key, "}") &&
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strings.Count(key, "{") == 1 {
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varValue, _ = repl.Get(strings.Trim(key, "{}"))
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} else {
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varValue = vars[key]
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}
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// see if any of the values given in the matcher match the actual value
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for _, v := range vals {
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matcherValExpanded := repl.ReplaceAll(v, "")
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var varStr string
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switch vv := varValue.(type) {
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case string:
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varStr = vv
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case fmt.Stringer:
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varStr = vv.String()
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case error:
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varStr = vv.Error()
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default:
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varStr = fmt.Sprintf("%v", vv)
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}
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if varStr == matcherValExpanded {
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return true
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}
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}
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}
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return false
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}
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2020-02-08 14:26:31 -05:00
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// MatchVarsRE matches the value of the context variables by a given regular expression.
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//
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// Upon a match, it adds placeholders to the request: `{http.regexp.name.capture_group}`
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// where `name` is the regular expression's name, and `capture_group` is either
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// the named or positional capture group from the expression itself. If no name
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// is given, then the placeholder omits the name: `{http.regexp.capture_group}`
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// (potentially leading to collisions).
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type MatchVarsRE map[string]*MatchRegexp
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// CaddyModule returns the Caddy module information.
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func (MatchVarsRE) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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ID: "http.matchers.vars_regexp",
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New: func() caddy.Module { return new(MatchVarsRE) },
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}
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}
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2020-09-25 18:50:26 -05:00
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// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
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func (m *MatchVarsRE) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
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if *m == nil {
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*m = make(map[string]*MatchRegexp)
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}
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// iterate to merge multiple matchers into one
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for d.Next() {
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var first, second, third string
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if !d.Args(&first, &second) {
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return d.ArgErr()
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}
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var name, field, val string
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if d.Args(&third) {
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name = first
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field = second
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val = third
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} else {
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field = first
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val = second
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}
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(*m)[field] = &MatchRegexp{Pattern: val, Name: name}
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if d.NextBlock(0) {
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return d.Err("malformed vars_regexp matcher: blocks are not supported")
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}
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}
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return nil
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}
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// Provision compiles m's regular expressions.
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func (m MatchVarsRE) Provision(ctx caddy.Context) error {
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for _, rm := range m {
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err := rm.Provision(ctx)
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if err != nil {
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return err
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}
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}
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return nil
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}
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// Match returns true if r matches m.
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func (m MatchVarsRE) Match(r *http.Request) bool {
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vars := r.Context().Value(VarsCtxKey).(map[string]any)
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repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
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for key, val := range m {
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var varValue any
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if strings.HasPrefix(key, "{") &&
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strings.HasSuffix(key, "}") &&
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strings.Count(key, "{") == 1 {
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varValue, _ = repl.Get(strings.Trim(key, "{}"))
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} else {
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varValue = vars[key]
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}
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var varStr string
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switch vv := varValue.(type) {
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case string:
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varStr = vv
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case fmt.Stringer:
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varStr = vv.String()
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case error:
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varStr = vv.Error()
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default:
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varStr = fmt.Sprintf("%v", vv)
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}
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valExpanded := repl.ReplaceAll(varStr, "")
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if match := val.Match(valExpanded, repl); match {
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return match
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}
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}
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return false
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}
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// Validate validates m's regular expressions.
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func (m MatchVarsRE) Validate() error {
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for _, rm := range m {
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err := rm.Validate()
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if err != nil {
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return err
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}
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}
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return nil
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}
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http: Change routes to sequential matcher evaluation (#2967)
Previously, all matchers in a route would be evaluated before any
handlers were executed, and a composite route of the matching routes
would be created. This made rewrites especially tricky, since the only
way to defer later matchers' evaluation was to wrap them in a subroute,
or to invoke a "rehandle" which often caused bugs.
Instead, this new sequential design evaluates each route's matchers then
its handlers in lock-step; matcher-handlers-matcher-handlers...
If the first matching route consists of a rewrite, then the second route
will be evaluated against the rewritten request, rather than the original
one, and so on.
This should do away with any need for rehandling.
I've also taken this opportunity to avoid adding new values to the
request context in the handler chain, as this creates a copy of the
Request struct, which may possibly lead to bugs like it has in the past
(see PR #1542, PR #1481, and maybe issue #2463). We now add all the
expected context values in the top-level handler at the server, then
any new values can be added to the variable table via the VarsCtxKey
context key, or just the GetVar/SetVar functions. In particular, we are
using this facility to convey dial information in the reverse proxy.
Had to be careful in one place as the middleware compilation logic has
changed, and moved a bit. We no longer compile a middleware chain per-
request; instead, we can compile it at provision-time, and defer only the
evaluation of matchers to request-time, which should slightly improve
performance. Doing this, however, we take advantage of multiple function
closures, and we also changed the use of HandlerFunc (function pointer)
to Handler (interface)... this led to a situation where, if we aren't
careful, allows one request routed a certain way to permanently change
the "next" handler for all/most other requests! We avoid this by making
a copy of the interface value (which is a lightweight pointer copy) and
using exclusively that within our wrapped handlers. This way, the
original stack frame is preserved in a "read-only" fashion. The comments
in the code describe this phenomenon.
This may very well be a breaking change for some configurations, however
I do not expect it to impact many people. I will make it clear in the
release notes that this change has occurred.
2020-01-09 12:00:13 -05:00
|
|
|
// GetVar gets a value out of the context's variable table by key.
|
|
|
|
// If the key does not exist, the return value will be nil.
|
2022-08-02 15:39:09 -05:00
|
|
|
func GetVar(ctx context.Context, key string) any {
|
|
|
|
varMap, ok := ctx.Value(VarsCtxKey).(map[string]any)
|
http: Change routes to sequential matcher evaluation (#2967)
Previously, all matchers in a route would be evaluated before any
handlers were executed, and a composite route of the matching routes
would be created. This made rewrites especially tricky, since the only
way to defer later matchers' evaluation was to wrap them in a subroute,
or to invoke a "rehandle" which often caused bugs.
Instead, this new sequential design evaluates each route's matchers then
its handlers in lock-step; matcher-handlers-matcher-handlers...
If the first matching route consists of a rewrite, then the second route
will be evaluated against the rewritten request, rather than the original
one, and so on.
This should do away with any need for rehandling.
I've also taken this opportunity to avoid adding new values to the
request context in the handler chain, as this creates a copy of the
Request struct, which may possibly lead to bugs like it has in the past
(see PR #1542, PR #1481, and maybe issue #2463). We now add all the
expected context values in the top-level handler at the server, then
any new values can be added to the variable table via the VarsCtxKey
context key, or just the GetVar/SetVar functions. In particular, we are
using this facility to convey dial information in the reverse proxy.
Had to be careful in one place as the middleware compilation logic has
changed, and moved a bit. We no longer compile a middleware chain per-
request; instead, we can compile it at provision-time, and defer only the
evaluation of matchers to request-time, which should slightly improve
performance. Doing this, however, we take advantage of multiple function
closures, and we also changed the use of HandlerFunc (function pointer)
to Handler (interface)... this led to a situation where, if we aren't
careful, allows one request routed a certain way to permanently change
the "next" handler for all/most other requests! We avoid this by making
a copy of the interface value (which is a lightweight pointer copy) and
using exclusively that within our wrapped handlers. This way, the
original stack frame is preserved in a "read-only" fashion. The comments
in the code describe this phenomenon.
This may very well be a breaking change for some configurations, however
I do not expect it to impact many people. I will make it clear in the
release notes that this change has occurred.
2020-01-09 12:00:13 -05:00
|
|
|
if !ok {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
return varMap[key]
|
|
|
|
}
|
|
|
|
|
|
|
|
// SetVar sets a value in the context's variable table with
|
|
|
|
// the given key. It overwrites any previous value with the
|
|
|
|
// same key.
|
2022-07-28 16:19:48 -05:00
|
|
|
//
|
|
|
|
// If the value is nil (note: non-nil interface with nil
|
|
|
|
// underlying value does not count) and the key exists in
|
|
|
|
// the table, the key+value will be deleted from the table.
|
2022-08-02 15:39:09 -05:00
|
|
|
func SetVar(ctx context.Context, key string, value any) {
|
|
|
|
varMap, ok := ctx.Value(VarsCtxKey).(map[string]any)
|
http: Change routes to sequential matcher evaluation (#2967)
Previously, all matchers in a route would be evaluated before any
handlers were executed, and a composite route of the matching routes
would be created. This made rewrites especially tricky, since the only
way to defer later matchers' evaluation was to wrap them in a subroute,
or to invoke a "rehandle" which often caused bugs.
Instead, this new sequential design evaluates each route's matchers then
its handlers in lock-step; matcher-handlers-matcher-handlers...
If the first matching route consists of a rewrite, then the second route
will be evaluated against the rewritten request, rather than the original
one, and so on.
This should do away with any need for rehandling.
I've also taken this opportunity to avoid adding new values to the
request context in the handler chain, as this creates a copy of the
Request struct, which may possibly lead to bugs like it has in the past
(see PR #1542, PR #1481, and maybe issue #2463). We now add all the
expected context values in the top-level handler at the server, then
any new values can be added to the variable table via the VarsCtxKey
context key, or just the GetVar/SetVar functions. In particular, we are
using this facility to convey dial information in the reverse proxy.
Had to be careful in one place as the middleware compilation logic has
changed, and moved a bit. We no longer compile a middleware chain per-
request; instead, we can compile it at provision-time, and defer only the
evaluation of matchers to request-time, which should slightly improve
performance. Doing this, however, we take advantage of multiple function
closures, and we also changed the use of HandlerFunc (function pointer)
to Handler (interface)... this led to a situation where, if we aren't
careful, allows one request routed a certain way to permanently change
the "next" handler for all/most other requests! We avoid this by making
a copy of the interface value (which is a lightweight pointer copy) and
using exclusively that within our wrapped handlers. This way, the
original stack frame is preserved in a "read-only" fashion. The comments
in the code describe this phenomenon.
This may very well be a breaking change for some configurations, however
I do not expect it to impact many people. I will make it clear in the
release notes that this change has occurred.
2020-01-09 12:00:13 -05:00
|
|
|
if !ok {
|
|
|
|
return
|
|
|
|
}
|
2022-07-28 16:19:48 -05:00
|
|
|
if value == nil {
|
|
|
|
if _, ok := varMap[key]; ok {
|
|
|
|
delete(varMap, key)
|
|
|
|
return
|
|
|
|
}
|
|
|
|
}
|
http: Change routes to sequential matcher evaluation (#2967)
Previously, all matchers in a route would be evaluated before any
handlers were executed, and a composite route of the matching routes
would be created. This made rewrites especially tricky, since the only
way to defer later matchers' evaluation was to wrap them in a subroute,
or to invoke a "rehandle" which often caused bugs.
Instead, this new sequential design evaluates each route's matchers then
its handlers in lock-step; matcher-handlers-matcher-handlers...
If the first matching route consists of a rewrite, then the second route
will be evaluated against the rewritten request, rather than the original
one, and so on.
This should do away with any need for rehandling.
I've also taken this opportunity to avoid adding new values to the
request context in the handler chain, as this creates a copy of the
Request struct, which may possibly lead to bugs like it has in the past
(see PR #1542, PR #1481, and maybe issue #2463). We now add all the
expected context values in the top-level handler at the server, then
any new values can be added to the variable table via the VarsCtxKey
context key, or just the GetVar/SetVar functions. In particular, we are
using this facility to convey dial information in the reverse proxy.
Had to be careful in one place as the middleware compilation logic has
changed, and moved a bit. We no longer compile a middleware chain per-
request; instead, we can compile it at provision-time, and defer only the
evaluation of matchers to request-time, which should slightly improve
performance. Doing this, however, we take advantage of multiple function
closures, and we also changed the use of HandlerFunc (function pointer)
to Handler (interface)... this led to a situation where, if we aren't
careful, allows one request routed a certain way to permanently change
the "next" handler for all/most other requests! We avoid this by making
a copy of the interface value (which is a lightweight pointer copy) and
using exclusively that within our wrapped handlers. This way, the
original stack frame is preserved in a "read-only" fashion. The comments
in the code describe this phenomenon.
This may very well be a breaking change for some configurations, however
I do not expect it to impact many people. I will make it clear in the
release notes that this change has occurred.
2020-01-09 12:00:13 -05:00
|
|
|
varMap[key] = value
|
|
|
|
}
|
|
|
|
|
2019-08-09 13:05:47 -05:00
|
|
|
// Interface guards
|
|
|
|
var (
|
2022-03-22 11:47:21 -05:00
|
|
|
_ MiddlewareHandler = (*VarsMiddleware)(nil)
|
|
|
|
_ caddyfile.Unmarshaler = (*VarsMiddleware)(nil)
|
|
|
|
_ RequestMatcher = (*VarsMatcher)(nil)
|
|
|
|
_ caddyfile.Unmarshaler = (*VarsMatcher)(nil)
|
2019-08-09 13:05:47 -05:00
|
|
|
)
|