我在解压缩之前压缩的字节流时遇到了问题。基本上，我尝试使用函数 bytes.NewReader() 创建一个阅读器，然后使用 gzip.NewReader() 函数解压流。最后，我想以字符串或字节格式返回实际值。

我知道 gzip.NewReader 需要 io.Reader 作为输入，但是，据我所知，类型 Reader 实现了接口(interface)io.Reader。我认为这不会导致任何错误，但我想知道在这种情况下可能是什么问题。如果你帮我解决这个问题，我将不胜感激!

如果您想知道这段文字是什么，

"amZzRUR2NHVtcVpiZHNROHJiTTNYeGdUSndGTlVDZC9jaElSK1lXcFlJOD0="

这是从我的客户端 python 脚本发送的示例输入。它使用 gzip 压缩，使用 AES128 加密，最后以 base64 编码，按此顺序进行。

客户端代码:

import time
import json
import requests
import random
import gzip
import base64

from Crypto.Cipher import AES

baseurl = 'http://0.0.0.0:80'
key = 'TfvY7I358yospfWKcoviZizOShpm5hyH'
iv = 'mb13KcoviZizvYhp'

MODE = AES.MODE_CFB
BLOCK_SIZE = 16
SEGMENT_SIZE = 128

def http_post(url, data):
    print('Going to make a request to {} with the following data: {}'.format(url, data))
    r = requests.post(url,
                  data=data,
                  headers={'Content-type': 'application/json; charset=utf-8',
                           'Connection': 'keep-alive'}, )
    if r.status_code != 200:
        print('Server returned unexpected response code {}, and content: {}'.format(r.status_code, r.content))
        return False
    else:
        data = r.json()
        return data


def post_sample_data(key, iv):
    fake_device_id = "MB88"
    Load_VA_Total_Mean = random.randint(1000, 100000)
    print('Data that should come back: {}'.format(Load_VA_Total_Mean))
    data = {'i': fake_device_id, 'p': [
    {'d': [54.3, 0, 99, 49.35, 3, 99, 51.533, 1, 98, 28964, 7348, 43590, Load_VA_Total_Mean, 10350, 55200, 49.7],
     't': time.time(), 'dt': 'p'}]}
    url = baseurl + '/realtimedata'
    encryption_key_reference = 1
    payload = '{}\n{}'.format(convert_pack(data, key, iv), encryption_key_reference)
    return http_post(url, payload)


def convert_pack(inputdict, key, iv):
    jsonpayload = json.dumps(inputdict)  # encode dict to json string
    gzippayload = gzip.compress(jsonpayload.encode('utf-8'))  # compress with gzip
    encryptedpayload = base64.b64encode(encrypt(key, iv, message))
    encoded = base64.b64encode(encryptedpayload)
    print('encoded: {}'.format(encoded))

    return str(encoded, encoding='utf-8')


def _pad_string(value):
    length = len(value)
    pad_size = BLOCK_SIZE - (length % BLOCK_SIZE)
    return value.ljust(length + pad_size, '\x00')


def encrypt(key, iv, plaintext):
    aes = AES.new(key, MODE, iv, segment_size=SEGMENT_SIZE)
    plaintext = _pad_string(plaintext)
    encrypted_text = aes.encrypt(plaintext)
    return encrypted_text


post_sample_data(key, iv)

服务器代码:

package main

import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"encoding/base64"
"fmt"
"io"
"compress/gzip"
"io/ioutil"
"bytes"
)

func main() {
    receivedText := "amZzRUR2NHVtcVpiZHNROHJiTTNYeGdUSndGTlVDZC9jaElSK1lXcFlJOD0="
    fmt.Println("encrypted + encoded + gzipped: ", originalText)
    key := []byte("TfvY7I358yospfWKcoviZizOShpm5hyH")

    text := decrypt(key, originalText)
    fmt.Println("decrypted: ", string(text))
    reader := bytes.NewReader(text)
    gzReader, err1 := gzip.NewReader(reader)
    fmt.Println(gzReader)

    if err1 != nil {
        fmt.Println("error1")
    }

    content, err2 := ioutil.ReadAll(gzReader)

    if err2 != nil {
        fmt.Println("error2")
    }

    fmt.Println(string(content))
}

func decrypt(key []byte, cryptoText string) []byte {
    ciphertext, _ := base64.StdEncoding.DecodeString(cryptoText)
    fmt.Println("decoded: ", string(ciphertext))
    block, err := aes.NewCipher(key)
    if err != nil {
        panic(err)
    }

    iv := []byte("mb13KcoviZizvYhp")
    stream := cipher.NewCFBDecrypter(block, iv)
    stream.XORKeyStream(ciphertext, ciphertext)

    return ciphertext
}

输出:

<nil>
error1
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
    panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x288 pc=0x10a9167]

goroutine 1 [running]:
io/ioutil.readAll.func1(0xc420037dd0)
    /usr/local/go/src/io/ioutil/ioutil.go:30 +0x119
panic(0x10c4580, 0x1154d00)
    /usr/local/go/src/runtime/panic.go:489 +0x2cf
compress/gzip.(*Reader).Read(0x0, 0xc420092000, 0x200, 0x200, 0x1024ade, 0xc400000008, 0xc4200120c0)
    /usr/local/go/src/compress/gzip/gunzip.go:247 +0x37
bytes.(*Buffer).ReadFrom(0xc420037d28, 0x11451a0, 0x0, 0xc420092000, 0x0, 0x200)
    /usr/local/go/src/bytes/buffer.go:179 +0x160
io/ioutil.readAll(0x11451a0, 0x0, 0x200, 0x0, 0x0, 0x0, 0x0, 0x0)
    /usr/local/go/src/io/ioutil/ioutil.go:33 +0x150
io/ioutil.ReadAll(0x11451a0, 0x0, 0x1, 0x7, 0x0, 0x0, 0x20)
    /usr/local/go/src/io/ioutil/ioutil.go:42 +0x3e
main.main()
    /Users/bkaankuguoglu/Desktop/Go-dev/tool-backend/tester.go:43 
+0x404
exit status 2

最佳答案

问题是您传递给 gz.NewReader() 的阅读器生成的“内容”不是有效的 gzip 流(数据)。如果 gzip.NewReader() 返回一个非 nil 错误(就像您的情况一样)，则返回的 gzReader 可能是 无(通常是)。

如果你传递一个有效的gzip流给gzip.NewReader()，返回的gzReader不会是nil，解码就会成功.

例如文本 "hello" 的 gzip 编码形式是:

[31 139 8 0 0 0 0 0 0 255 203 72 205 201 201 7 0 134 166 16 54 5 0 0 0]

使用这个作为输入:

data := []byte{31, 139, 8, 0, 0, 0, 0, 0, 0,
    255, 203, 72, 205, 201, 201, 7, 0, 134, 166, 16, 54, 5, 0, 0, 0}
reader := bytes.NewReader(data)
// The rest is unchanged

它有效，输出是(在 Go Playground 上尝试):

&{[31 139 8 0 0 0 0 0 0 255 203 72 205 201 201 7 0 134 166 16 54 5 0 0 0] 0 -1}
&{{ [] 0001-01-01 00:00:00 +0000 UTC  255} 0x10440260 0x10462000 0 0 [31 139 8 0 0 0 0 0 0 255 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] <nil> true}
hello

关于python - 当 Reader 类型作为输入时，gzip.NewReader() 返回 nil，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44884766/