caddy/modules/caddyhttp/vars.go
Francis Lavoie 85375861f6
caddyhttp: Fix vars_regexp matcher with placeholders (#5408)
Changed to match the `vars` matcher's logic for handling placeholders
2023-03-02 09:01:54 -07:00

337 lines
8.6 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 caddyhttp
import (
"context"
"fmt"
"net/http"
"strings"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
)
func init() {
caddy.RegisterModule(VarsMiddleware{})
caddy.RegisterModule(VarsMatcher{})
caddy.RegisterModule(MatchVarsRE{})
}
// VarsMiddleware is an HTTP middleware which sets variables to
// have values that can be used in the HTTP request handler
// chain. The primary way to access variables is with placeholders,
// which have the form: `{http.vars.variable_name}`, or with
// the `vars` and `vars_regexp` request matchers.
//
// The key is the variable name, and the value is the value of the
// variable. Both the name and value may use or contain placeholders.
type VarsMiddleware map[string]any
// CaddyModule returns the Caddy module information.
func (VarsMiddleware) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.handlers.vars",
New: func() caddy.Module { return new(VarsMiddleware) },
}
}
func (m VarsMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
vars := r.Context().Value(VarsCtxKey).(map[string]any)
repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
for k, v := range m {
keyExpanded := repl.ReplaceAll(k, "")
if valStr, ok := v.(string); ok {
v = repl.ReplaceAll(valStr, "")
}
vars[keyExpanded] = v
}
return next.ServeHTTP(w, r)
}
// UnmarshalCaddyfile implements caddyfile.Unmarshaler. Syntax:
//
// vars [<name> <val>] {
// <name> <val>
// ...
// }
func (m *VarsMiddleware) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
if *m == nil {
*m = make(VarsMiddleware)
}
nextVar := func(headerLine bool) error {
if headerLine {
// header line is optional
if !d.NextArg() {
return nil
}
}
varName := d.Val()
if !d.NextArg() {
return d.ArgErr()
}
varValue := d.ScalarVal()
(*m)[varName] = varValue
if d.NextArg() {
return d.ArgErr()
}
return nil
}
for d.Next() {
if err := nextVar(true); err != nil {
return err
}
for nesting := d.Nesting(); d.NextBlock(nesting); {
if err := nextVar(false); err != nil {
return err
}
}
}
return nil
}
// VarsMatcher is an HTTP request matcher which can match
// requests based on variables in the context or placeholder
// values. The key is the placeholder or name of the variable,
// and the values are possible values the variable can be in
// order to match (logical OR'ed).
//
// If the key is surrounded by `{ }` it is assumed to be a
// placeholder. Otherwise, it will be considered a variable
// name.
//
// Placeholders in the keys are not expanded, but
// placeholders in the values are.
type VarsMatcher map[string][]string
// CaddyModule returns the Caddy module information.
func (VarsMatcher) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.matchers.vars",
New: func() caddy.Module { return new(VarsMatcher) },
}
}
// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
func (m *VarsMatcher) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
if *m == nil {
*m = make(map[string][]string)
}
for d.Next() {
var field string
if !d.Args(&field) {
return d.Errf("malformed vars matcher: expected field name")
}
vals := d.RemainingArgs()
if len(vals) == 0 {
return d.Errf("malformed vars matcher: expected at least one value to match against")
}
(*m)[field] = append((*m)[field], vals...)
if d.NextBlock(0) {
return d.Err("malformed vars matcher: blocks are not supported")
}
}
return nil
}
// Match matches a request based on variables in the context,
// or placeholders if the key is not a variable.
func (m VarsMatcher) Match(r *http.Request) bool {
if len(m) == 0 {
return true
}
vars := r.Context().Value(VarsCtxKey).(map[string]any)
repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
for key, vals := range m {
var varValue any
if strings.HasPrefix(key, "{") &&
strings.HasSuffix(key, "}") &&
strings.Count(key, "{") == 1 {
varValue, _ = repl.Get(strings.Trim(key, "{}"))
} else {
varValue = vars[key]
}
// see if any of the values given in the matcher match the actual value
for _, v := range vals {
matcherValExpanded := repl.ReplaceAll(v, "")
var varStr string
switch vv := varValue.(type) {
case string:
varStr = vv
case fmt.Stringer:
varStr = vv.String()
case error:
varStr = vv.Error()
default:
varStr = fmt.Sprintf("%v", vv)
}
if varStr == matcherValExpanded {
return true
}
}
}
return false
}
// MatchVarsRE matches the value of the context variables by a given regular expression.
//
// Upon a match, it adds placeholders to the request: `{http.regexp.name.capture_group}`
// where `name` is the regular expression's name, and `capture_group` is either
// the named or positional capture group from the expression itself. If no name
// is given, then the placeholder omits the name: `{http.regexp.capture_group}`
// (potentially leading to collisions).
type MatchVarsRE map[string]*MatchRegexp
// CaddyModule returns the Caddy module information.
func (MatchVarsRE) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.matchers.vars_regexp",
New: func() caddy.Module { return new(MatchVarsRE) },
}
}
// UnmarshalCaddyfile implements caddyfile.Unmarshaler.
func (m *MatchVarsRE) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
if *m == nil {
*m = make(map[string]*MatchRegexp)
}
for d.Next() {
var first, second, third string
if !d.Args(&first, &second) {
return d.ArgErr()
}
var name, field, val string
if d.Args(&third) {
name = first
field = second
val = third
} else {
field = first
val = second
}
(*m)[field] = &MatchRegexp{Pattern: val, Name: name}
if d.NextBlock(0) {
return d.Err("malformed vars_regexp matcher: blocks are not supported")
}
}
return nil
}
// Provision compiles m's regular expressions.
func (m MatchVarsRE) Provision(ctx caddy.Context) error {
for _, rm := range m {
err := rm.Provision(ctx)
if err != nil {
return err
}
}
return nil
}
// Match returns true if r matches m.
func (m MatchVarsRE) Match(r *http.Request) bool {
vars := r.Context().Value(VarsCtxKey).(map[string]any)
repl := r.Context().Value(caddy.ReplacerCtxKey).(*caddy.Replacer)
for key, val := range m {
var varValue any
if strings.HasPrefix(key, "{") &&
strings.HasSuffix(key, "}") &&
strings.Count(key, "{") == 1 {
varValue, _ = repl.Get(strings.Trim(key, "{}"))
} else {
varValue = vars[key]
}
var varStr string
switch vv := varValue.(type) {
case string:
varStr = vv
case fmt.Stringer:
varStr = vv.String()
case error:
varStr = vv.Error()
default:
varStr = fmt.Sprintf("%v", vv)
}
valExpanded := repl.ReplaceAll(varStr, "")
if match := val.Match(valExpanded, repl); match {
return match
}
}
return false
}
// Validate validates m's regular expressions.
func (m MatchVarsRE) Validate() error {
for _, rm := range m {
err := rm.Validate()
if err != nil {
return err
}
}
return nil
}
// 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.
func GetVar(ctx context.Context, key string) any {
varMap, ok := ctx.Value(VarsCtxKey).(map[string]any)
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.
//
// 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.
func SetVar(ctx context.Context, key string, value any) {
varMap, ok := ctx.Value(VarsCtxKey).(map[string]any)
if !ok {
return
}
if value == nil {
if _, ok := varMap[key]; ok {
delete(varMap, key)
return
}
}
varMap[key] = value
}
// Interface guards
var (
_ MiddlewareHandler = (*VarsMiddleware)(nil)
_ caddyfile.Unmarshaler = (*VarsMiddleware)(nil)
_ RequestMatcher = (*VarsMatcher)(nil)
_ caddyfile.Unmarshaler = (*VarsMatcher)(nil)
)