Franz Kafka
7be03b4017
Update LICENSE file and add AGPL header to all source files. AGPLv3 ensures that if someone runs Kafka as a network service and modifies it, they must release their source code under the same license.
104 lines
3.1 KiB
Go
104 lines
3.1 KiB
Go
// kafka — a privacy-respecting metasearch engine
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// Copyright (C) 2026-present metamorphosis-dev
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package middleware
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import (
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"net/http"
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"strconv"
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"strings"
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)
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// CORSConfig controls Cross-Origin Resource Sharing headers.
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type CORSConfig struct {
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// AllowedOrigins is a list of allowed origin patterns.
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// Use "*" to allow all origins, or specific domains like "https://example.com".
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AllowedOrigins []string
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// AllowedMethods defaults to GET, POST, OPTIONS if empty.
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AllowedMethods []string
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// AllowedHeaders defaults to Content-Type, Authorization if empty.
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AllowedHeaders []string
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// ExposedHeaders lists headers the browser can access from the response.
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ExposedHeaders []string
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// MaxAge is the preflight cache duration in seconds (default: 3600).
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MaxAge int
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}
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// CORS returns a middleware that sets CORS headers on all responses
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// and handles OPTIONS preflight requests.
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func CORS(cfg CORSConfig) func(http.Handler) http.Handler {
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origins := cfg.AllowedOrigins
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if len(origins) == 0 {
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origins = []string{"*"}
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}
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methods := cfg.AllowedMethods
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if len(methods) == 0 {
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methods = []string{"GET", "POST", "OPTIONS"}
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}
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headers := cfg.AllowedHeaders
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if len(headers) == 0 {
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headers = []string{"Content-Type", "Authorization", "X-Search-Token", "X-Brave-Access-Token"}
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}
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maxAge := cfg.MaxAge
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if maxAge <= 0 {
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maxAge = 3600
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}
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methodsStr := strings.Join(methods, ", ")
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headersStr := strings.Join(headers, ", ")
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exposedStr := strings.Join(cfg.ExposedHeaders, ", ")
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maxAgeStr := strconv.Itoa(maxAge)
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return func(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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origin := r.Header.Get("Origin")
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// Determine the allowed origin for this request.
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allowedOrigin := ""
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for _, o := range origins {
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if o == "*" {
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allowedOrigin = "*"
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break
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}
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if o == origin {
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allowedOrigin = origin
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break
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}
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}
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if allowedOrigin != "" {
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w.Header().Set("Access-Control-Allow-Origin", allowedOrigin)
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w.Header().Set("Access-Control-Allow-Methods", methodsStr)
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w.Header().Set("Access-Control-Allow-Headers", headersStr)
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if exposedStr != "" {
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w.Header().Set("Access-Control-Expose-Headers", exposedStr)
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}
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w.Header().Set("Access-Control-Max-Age", maxAgeStr)
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}
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// Handle preflight.
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if r.Method == http.MethodOptions {
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w.WriteHeader(http.StatusNoContent)
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return
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}
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next.ServeHTTP(w, r)
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})
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}
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}
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