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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package middleware
import (
"bufio"
"context"
"crypto/rand"
"encoding/base32"
"encoding/binary"
"io"
"sync"
"time"
"codeberg.org/gruf/go-kv"
"github.com/gin-gonic/gin"
"github.com/superseriousbusiness/gotosocial/internal/log"
)
type ctxType string
var (
// ridCtxKey is the key underwhich we store request IDs in a context.
ridCtxKey ctxType = "id"
// crand provides buffered reads of random input.
crand = bufio.NewReader(rand.Reader)
mrand sync.Mutex
// base32enc is a base 32 encoding based on a human-readable character set (no padding).
base32enc = base32.NewEncoding("0123456789abcdefghjkmnpqrstvwxyz").WithPadding(-1)
)
// generateID generates a new ID string.
func generateID() string {
// 0:8 = timestamp
// 8:12 = entropy
//
// inspired by ULID.
b := make([]byte, 12)
// Get current time in milliseconds.
ms := uint64(time.Now().UnixMilli())
// Store binary time data in byte buffer.
binary.LittleEndian.PutUint64(b[0:8], ms)
mrand.Lock()
// Read random bits into buffer end.
_, _ = io.ReadFull(crand, b[8:12])
mrand.Unlock()
// Encode the binary time+entropy ID.
return base32enc.EncodeToString(b)
}
// RequestID fetches the stored request ID from context.
func RequestID(ctx context.Context) string {
id, _ := ctx.Value(ridCtxKey).(string)
return id
}
// AddRequestID returns a gin middleware which adds a unique ID to each request (both response header and context).
func AddRequestID(header string) gin.HandlerFunc {
log.Hook(func(ctx context.Context, kvs []kv.Field) []kv.Field {
if id, _ := ctx.Value(ridCtxKey).(string); id != "" {
// Add stored request ID to log entry fields.
return append(kvs, kv.Field{K: "requestID", V: id})
}
return kvs
})
return func(c *gin.Context) {
// Look for existing ID.
id := c.GetHeader(header)
if id == "" {
// Generate new ID.
//
// 0:8 = timestamp
// 8:12 = entropy
id = generateID()
// Set the request ID in the req header in case we pass the request along
// to another service
c.Request.Header.Set(header, id)
}
// Store request ID in new request ctx and set new gin request obj.
ctx := context.WithValue(c.Request.Context(), ridCtxKey, id)
c.Request = c.Request.WithContext(ctx)
// Set the request ID in the rsp header.
c.Writer.Header().Set(header, id)
}
}
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