gtsocial-umbx

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requestid.go (2552B)

      1 // GoToSocial
      2 // Copyright (C) GoToSocial Authors admin@gotosocial.org
      3 // SPDX-License-Identifier: AGPL-3.0-or-later
      4 //
      5 // This program is free software: you can redistribute it and/or modify
      6 // it under the terms of the GNU Affero General Public License as published by
      7 // the Free Software Foundation, either version 3 of the License, or
      8 // (at your option) any later version.
      9 //
     10 // This program is distributed in the hope that it will be useful,
     11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
     12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     13 // GNU Affero General Public License for more details.
     14 //
     15 // You should have received a copy of the GNU Affero General Public License
     16 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
     17 
     18 package middleware
     19 
     20 import (
     21 	"bufio"
     22 	"crypto/rand"
     23 	"encoding/base32"
     24 	"encoding/binary"
     25 	"io"
     26 	"sync"
     27 	"time"
     28 
     29 	"github.com/gin-gonic/gin"
     30 	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
     31 )
     32 
     33 var (
     34 	// crand provides buffered reads of random input.
     35 	crand = bufio.NewReader(rand.Reader)
     36 	mrand sync.Mutex
     37 
     38 	// base32enc is a base 32 encoding based on a human-readable character set (no padding).
     39 	base32enc = base32.NewEncoding("0123456789abcdefghjkmnpqrstvwxyz").WithPadding(-1)
     40 )
     41 
     42 // generateID generates a new ID string.
     43 func generateID() string {
     44 	// 0:8  = timestamp
     45 	// 8:12 = entropy
     46 	//
     47 	// inspired by ULID.
     48 	b := make([]byte, 12)
     49 
     50 	// Get current time in milliseconds.
     51 	ms := uint64(time.Now().UnixMilli())
     52 
     53 	// Store binary time data in byte buffer.
     54 	binary.LittleEndian.PutUint64(b[0:8], ms)
     55 
     56 	mrand.Lock()
     57 	// Read random bits into buffer end.
     58 	_, _ = io.ReadFull(crand, b[8:12])
     59 	mrand.Unlock()
     60 
     61 	// Encode the binary time+entropy ID.
     62 	return base32enc.EncodeToString(b)
     63 }
     64 
     65 // AddRequestID returns a gin middleware which adds a unique ID to each request (both response header and context).
     66 func AddRequestID(header string) gin.HandlerFunc {
     67 	return func(c *gin.Context) {
     68 		id := c.GetHeader(header)
     69 		// Have we found anything?
     70 		if id == "" {
     71 			// Generate new ID.
     72 			//
     73 			// 0:8  = timestamp
     74 			// 8:12 = entropy
     75 			id = generateID()
     76 			// Set the request ID in the req header in case we pass the request along
     77 			// to another service
     78 			c.Request.Header.Set(header, id)
     79 		}
     80 
     81 		// Store request ID in new request context and set on gin ctx.
     82 		ctx := gtscontext.SetRequestID(c.Request.Context(), id)
     83 		c.Request = c.Request.WithContext(ctx)
     84 
     85 		// Set the request ID in the rsp header.
     86 		c.Writer.Header().Set(header, id)
     87 	}
     88 }