mirror of
https://wget.la/https://github.com/Wxw-Gu/WechatExplorer
synced 2026-08-18 12:07:01 +08:00
feat: 内置微信连接器并完善 Agent 查询能力
This commit is contained in:
Wxw-Gu
@@ -0,0 +1,232 @@
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package messaging
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import (
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"bytes"
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"context"
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"crypto/aes"
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"crypto/md5"
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"crypto/rand"
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"encoding/base64"
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"encoding/hex"
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"fmt"
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"io"
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"net/http"
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"net/url"
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"strings"
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"time"
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"github.com/Wxw-Gu/WechatExplorer/services/wechat-connector/ilink"
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)
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const cdnBaseURL = "https://novac2c.cdn.weixin.qq.com/c2c"
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// UploadedFile holds the result of a CDN upload.
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type UploadedFile struct {
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DownloadParam string // encrypted query param for download
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AESKeyHex string // hex-encoded AES key
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FileSize int // plaintext size
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CipherSize int // ciphertext size
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}
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// UploadFileToCDN encrypts and uploads a file to the WeChat CDN.
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func UploadFileToCDN(ctx context.Context, client *ilink.Client, data []byte, toUserID string, mediaType int) (*UploadedFile, error) {
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// Generate random filekey and AES key
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filekey := make([]byte, 16)
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aeskey := make([]byte, 16)
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if _, err := rand.Read(filekey); err != nil {
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return nil, fmt.Errorf("generate filekey: %w", err)
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}
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if _, err := rand.Read(aeskey); err != nil {
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return nil, fmt.Errorf("generate aeskey: %w", err)
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}
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filekeyHex := hex.EncodeToString(filekey)
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aeskeyHex := hex.EncodeToString(aeskey)
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// Calculate MD5 of plaintext
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hash := md5.Sum(data)
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rawMD5 := hex.EncodeToString(hash[:])
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// Calculate ciphertext size (PKCS7 padding)
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cipherSize := aesECBPaddedSize(len(data))
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// Get upload URL from iLink API
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uploadReq := &ilink.GetUploadURLRequest{
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FileKey: filekeyHex,
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MediaType: mediaType,
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ToUserID: toUserID,
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RawSize: len(data),
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RawFileMD5: rawMD5,
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FileSize: cipherSize,
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NoNeedThumb: true,
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AESKey: aeskeyHex,
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BaseInfo: ilink.BaseInfo{},
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}
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uploadResp, err := client.GetUploadURL(ctx, uploadReq)
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if err != nil {
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return nil, fmt.Errorf("get upload URL: %w", err)
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}
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if uploadResp.Ret != 0 {
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return nil, fmt.Errorf("get upload URL failed: ret=%d errmsg=%s", uploadResp.Ret, uploadResp.ErrMsg)
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}
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// Encrypt data with AES-128-ECB
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encrypted, err := encryptAESECB(data, aeskey)
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if err != nil {
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return nil, fmt.Errorf("encrypt: %w", err)
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}
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// Upload to CDN: prefer server-provided full URL, fall back to param-based construction
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cdnURL := strings.TrimSpace(uploadResp.UploadFullURL)
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if cdnURL == "" {
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if uploadResp.UploadParam == "" {
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return nil, fmt.Errorf("getuploadurl returned no upload URL (need upload_full_url or upload_param)")
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}
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cdnURL = fmt.Sprintf("%s/upload?encrypted_query_param=%s&filekey=%s",
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cdnBaseURL, url.QueryEscape(uploadResp.UploadParam), url.QueryEscape(filekeyHex))
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}
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downloadParam, err := uploadToCDN(ctx, encrypted, cdnURL)
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if err != nil {
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return nil, fmt.Errorf("CDN upload: %w", err)
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}
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return &UploadedFile{
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DownloadParam: downloadParam,
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AESKeyHex: aeskeyHex,
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FileSize: len(data),
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CipherSize: cipherSize,
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}, nil
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}
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// AESKeyToBase64 converts a hex AES key to base64 format for message items.
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func AESKeyToBase64(hexKey string) string {
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return base64.StdEncoding.EncodeToString([]byte(hexKey))
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}
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// DownloadFileFromCDN downloads and decrypts a file from the WeChat CDN.
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func DownloadFileFromCDN(ctx context.Context, encryptQueryParam, aesKeyBase64 string) ([]byte, error) {
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// Decode AES key: base64 -> hex string -> raw bytes
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aesKeyHexBytes, err := base64.StdEncoding.DecodeString(aesKeyBase64)
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if err != nil {
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return nil, fmt.Errorf("decode AES key base64: %w", err)
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}
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aesKey, err := hex.DecodeString(string(aesKeyHexBytes))
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if err != nil {
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return nil, fmt.Errorf("decode AES key hex: %w", err)
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}
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// Download encrypted data from CDN
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downloadURL := fmt.Sprintf("%s/download?encrypted_query_param=%s",
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cdnBaseURL, url.QueryEscape(encryptQueryParam))
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reqCtx, cancel := context.WithTimeout(ctx, 60*time.Second)
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defer cancel()
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req, err := http.NewRequestWithContext(reqCtx, http.MethodGet, downloadURL, nil)
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if err != nil {
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return nil, fmt.Errorf("create download request: %w", err)
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}
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resp, err := http.DefaultClient.Do(req)
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if err != nil {
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return nil, fmt.Errorf("download from CDN: %w", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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body, _ := io.ReadAll(resp.Body)
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return nil, fmt.Errorf("CDN download HTTP %d: %s", resp.StatusCode, string(body))
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}
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encrypted, err := io.ReadAll(resp.Body)
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if err != nil {
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return nil, fmt.Errorf("read CDN response: %w", err)
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}
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// Decrypt AES-128-ECB
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return decryptAESECB(encrypted, aesKey)
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}
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// decryptAESECB decrypts data encrypted with AES-128-ECB and removes PKCS7 padding.
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func decryptAESECB(ciphertext, key []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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if len(ciphertext)%aes.BlockSize != 0 {
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return nil, fmt.Errorf("ciphertext is not a multiple of block size")
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}
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plaintext := make([]byte, len(ciphertext))
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for i := 0; i < len(ciphertext); i += aes.BlockSize {
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block.Decrypt(plaintext[i:i+aes.BlockSize], ciphertext[i:i+aes.BlockSize])
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}
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// Remove PKCS7 padding
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if len(plaintext) == 0 {
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return plaintext, nil
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}
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padLen := int(plaintext[len(plaintext)-1])
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if padLen > aes.BlockSize || padLen == 0 {
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return nil, fmt.Errorf("invalid PKCS7 padding")
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}
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return plaintext[:len(plaintext)-padLen], nil
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}
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func uploadToCDN(ctx context.Context, encrypted []byte, cdnURL string) (string, error) {
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req, err := http.NewRequestWithContext(ctx, http.MethodPost, cdnURL, bytes.NewReader(encrypted))
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if err != nil {
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return "", err
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}
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req.Header.Set("Content-Type", "application/octet-stream")
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client := &http.Client{Timeout: 60 * time.Second}
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resp, err := client.Do(req)
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if err != nil {
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return "", err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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body, _ := io.ReadAll(resp.Body)
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return "", fmt.Errorf("CDN upload HTTP %d: %s", resp.StatusCode, string(body))
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}
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downloadParam := resp.Header.Get("X-Encrypted-Param")
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if downloadParam == "" {
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return "", fmt.Errorf("CDN upload: missing X-Encrypted-Param header")
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}
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return downloadParam, nil
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}
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// encryptAESECB encrypts data using AES-128-ECB with PKCS7 padding.
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func encryptAESECB(plaintext, key []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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// PKCS7 padding
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padLen := aes.BlockSize - (len(plaintext) % aes.BlockSize)
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padded := make([]byte, len(plaintext)+padLen)
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copy(padded, plaintext)
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for i := len(plaintext); i < len(padded); i++ {
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padded[i] = byte(padLen)
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}
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// ECB mode: encrypt each block independently
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encrypted := make([]byte, len(padded))
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for i := 0; i < len(padded); i += aes.BlockSize {
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block.Encrypt(encrypted[i:i+aes.BlockSize], padded[i:i+aes.BlockSize])
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}
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return encrypted, nil
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}
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func aesECBPaddedSize(plaintextSize int) int {
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return (plaintextSize/aes.BlockSize + 1) * aes.BlockSize
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}
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