06.使用GO上传图片

前言

需要批量上传图片到图床，之前用python写脚本倒是很简单，不过GO因为并发太强大了，所以这次用GO来试试

基础版

构建一个上传图片的请求，主要代码在imgkr()函数中

package main
import (
    "bytes"
    "fmt"
    "golang.org/x/net/publicsuffix"
    "io"
    "math/rand"
    "mime/multipart"
    "net/http"
    "net/http/cookiejar"
    "os"
    "path/filepath"
)
var client http.Client
func imgkr() {
    // 要上传的文件
    imgFilePath := "/Users/d4m1ts/d4m1ts/Upload/logo.png"
    file, _ := os.Open(imgFilePath)
    defer file.Close()
    // 设置body数据并写入缓冲区
    bodyBuff := bytes.NewBufferString("") //bodyBuff := &bytes.Buffer{}
    bodyWriter := multipart.NewWriter(bodyBuff)
    _ = bodyWriter.SetBoundary(fmt.Sprintf("-----------------------------%d", rand.Int()))
    // 加入图片二进制
    part, _ := bodyWriter.CreateFormFile("source", filepath.Base(file.Name()))
    _, _ = io.Copy(part, file)
    // 其他字段
    _ = bodyWriter.WriteField("a", "b")
    // 自动补充boundary结尾
    bodyWriter.Close()
    fmt.Println(bodyBuff) //构建的完整数据包，没有header
    // 组合创建数据包
    req, _ := http.NewRequest("POST", "http://127.0.0.1:8000", bodyBuff)
    req.ContentLength = int64(bodyBuff.Len())
    req.Header.Set("Content-Type", bodyWriter.FormDataContentType())
    req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0")
    client.Do(req)
}
func main() {
    jar, _ := cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
    client = http.Client{Jar: jar}
    imgkr()
}

接收到的数据包

进阶版

上面的数据包大概是没什么问题，但是图片的Content-Type是application/octet-stream，而一般情况下图片的应该是形如image/png
分析了一下原因，是因为CreateFormFile函数里面硬编码了

看里面的一些函数，也没找到直接设置这个地方的Content-Type的，所以我决定根据他的规则重新写一下。

分析这个函数，前面h是header头，也是我们要修改的地方，后面是调用*Writer.CreatePart，我们也模拟这个行为就可以了
所以微调一下代码（直接给代码复制粘贴过来改就可以了，也可以直接重写CreateFormFile函数，后者稍微麻烦一点点）

效果

目标达成，完整代码

package main
import (
    "bytes"
    "fmt"
    "golang.org/x/net/publicsuffix"
    "io"
    "math/rand"
    "mime/multipart"
    "net/http"
    "net/http/cookiejar"
    "net/textproto"
    "os"
    "path/filepath"
    "strings"
)
var client http.Client
var quoteEscaper = strings.NewReplacer("\\", "\\\\", `"`, "\\\"")
func escapeQuotes(s string) string {
    return quoteEscaper.Replace(s)
}
func imgkr() {
    // 要上传的文件
    imgFilePath := "/Users/d4m1ts/d4m1ts/Upload/logo.png"
    file, _ := os.Open(imgFilePath)
    defer file.Close()
    // 设置body数据并写入缓冲区
    bodyBuff := bytes.NewBufferString("") //bodyBuff := &bytes.Buffer{}
    bodyWriter := multipart.NewWriter(bodyBuff)
    _ = bodyWriter.SetBoundary(fmt.Sprintf("-----------------------------%d", rand.Int()))
    // 加入图片二进制
    h := make(textproto.MIMEHeader)
    h.Set("Content-Disposition", fmt.Sprintf(`form-data; name="%s"; filename="%s"`, escapeQuotes("source"), escapeQuotes(filepath.Base(file.Name()))))
    h.Set("Content-Type", "image/png")
    part, _ := bodyWriter.CreatePart(h)
    _, _ = io.Copy(part, file)
    // 其他字段
    _ = bodyWriter.WriteField("a", "b")
    // 自动补充boundary结尾
    bodyWriter.Close()
    fmt.Println(bodyBuff) //构建的完整数据包，没有header
    // 组合创建数据包
    req, _ := http.NewRequest("POST", "http://127.0.0.1:8000", bodyBuff)
    req.ContentLength = int64(bodyBuff.Len())
    req.Header.Set("Content-Type", bodyWriter.FormDataContentType())
    req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0")
    client.Do(req)
}
func main() {
    jar, _ := cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
    client = http.Client{Jar: jar}
    imgkr()
}

完整版

写了一个上传到https://imgtu.com/的，大家有需可以参考
为了方便以后的复制粘贴，给构造上传图片请求单独写到imgkr()函数中的，不然应该给结果解析也写里面的

package main
import (
    "bytes"
    "fmt"
    "golang.org/x/net/publicsuffix"
    "io"
    "io/ioutil"
    "math/rand"
    "mime/multipart"
    "net/http"
    "net/http/cookiejar"
    "net/textproto"
    "os"
    "path/filepath"
    "regexp"
    "strings"
    "time"
    "github.com/json-iterator/go"
)
var client http.Client
var quoteEscaper = strings.NewReplacer("\\", "\\\\", `"`, "\\\"")
func escapeQuotes(s string) string {
    return quoteEscaper.Replace(s)
}
/*
获取上传图片需要的token
 */
func getToken() string {
    u := "https://imgtu.com/"
    req, _ := http.NewRequest("GET", u, nil)
    req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0")
    resp, _ := client.Do(req)
    res,_ := ioutil.ReadAll(resp.Body)
    regex, _ := regexp.Compile("PF.obj.config.auth_token = \"(.*?)\";")
    if regex.MatchString(string(res)){
        token := regex.FindStringSubmatch(string(res))[1]
        return token
    }
    return ""
}
/*
构造上传请求
 */
func imgkr(token string, imgFilePath string) *http.Request {
    // 上传网址
    target := "https://imgtu.com/json"
    // 要上传的文件
    file, _ := os.Open(imgFilePath)
    defer file.Close()
    // 设置body数据并写入缓冲区
    bodyBuff := bytes.NewBufferString("") //bodyBuff := &bytes.Buffer{}
    bodyWriter := multipart.NewWriter(bodyBuff)
    _ = bodyWriter.SetBoundary(fmt.Sprintf("-----------------------------%d", rand.Int()))
    // 加入图片二进制
    h := make(textproto.MIMEHeader)
    h.Set("Content-Disposition", fmt.Sprintf(`form-data; name="%s"; filename="%s"`, escapeQuotes("source"), escapeQuotes(filepath.Base(file.Name()))))
    h.Set("Content-Type", "image/png")
    part, _ := bodyWriter.CreatePart(h)
    _, _ = io.Copy(part, file)
    // 其他字段
    _ = bodyWriter.WriteField("type", "file")
    _ = bodyWriter.WriteField("action", "upload")
    _ = bodyWriter.WriteField("timestamp", fmt.Sprintf("%d", time.Now().UnixNano()/1e6))
    _ = bodyWriter.WriteField("auth_token", token)
    _ = bodyWriter.WriteField("nsfw", "0")
    // 自动补充boundary结尾
    _ = bodyWriter.Close()
    //fmt.Println(bodyBuff) //构建的完整数据包，没有header
    // 创建请求
    req, _ := http.NewRequest("POST", target, bodyBuff)
    req.ContentLength = int64(bodyBuff.Len())
    req.Header.Set("Content-Type", bodyWriter.FormDataContentType())
    req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:89.0) Gecko/20100101 Firefox/89.0")
    return req
}
func main() {
    jar, _ := cookiejar.New(&cookiejar.Options{PublicSuffixList: publicsuffix.List})
    client = http.Client{Jar: jar}
    token := getToken()
    req := imgkr(token, "/Users/d4m1ts/d4m1ts/Upload/logo.png")
    resp, _ := client.Do(req)
    res, _ := ioutil.ReadAll(resp.Body)
    imageUrl := jsoniter.Get(res, "image").Get("url")
    fmt.Println(imageUrl.ToString())
}

效果