腾讯OCR文字识别API调用

package main

import (
	"bytes"
	"crypto/md5"
	"encoding/base64"
	"encoding/json"
	"fmt"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"os"
	"sort"
	"strconv"
	"strings"
	"time"
)

const APPID = 2156348148x
const APPKEY = "XFpS522Lm1kPcAQ3x"
const OCRURL = "https://api.ai.qq.com/fcgi-bin/ocr/ocr_generalocr"

type Param struct {
	key string
	value string
}

type RequestData struct {
	AppId int
	TimeStamp int
	NonceStr string
	Sign string
	Image string
	Params string
}

type Response struct {
	Ret int `json:"ret"`
	Msg string `json:"msg"`
	Data struct {
		Item_list [] struct {
			Item string `json:"item"`
			Itemstring string `json:"itemstring"`
			Itemcoord [] struct {
				X int `json:"x"`
				Y int `json:"y"`
				Width int `json:"width"`
				Height int `json:"height"`
			} `json:"itemcoord"`
			Words [] struct {
				Character string `json:"character"`
				Confidence float64 `json:"confidence"`
			} `json:"words"`
		} `json:"item_list"`
	} `json:"data"`
}

func main() {
	data, err := GetRequestData("./ntscreenshot_20200905_145215.png")
	if err != nil {
		log.Println(err)
		return
	}
	request, err := http.NewRequest("POST", OCRURL, bytes.NewBufferString(data.Params))
	if err != nil {
		log.Println(err)
		return
	}
	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	client := http.Client{}
	response, err := client.Do(request)
	if err != nil {
		log.Println(err)
		return
	}
	defer response.Body.Close()
	var rsp Response
	err = json.NewDecoder(response.Body).Decode(&rsp)
	if err != nil {
		log.Println("json decode error", err)
		return
	}
	fmt.Println(rsp)
}

func GetSign(params []Param) string {
	sort.Slice(params, func(i, j int)bool {
		return params[i].key < params[j].key
	})
	var s string
	for _, param := range params {
		if len(param.value) > 0 {
			s += fmt.Sprintf("%s=%s&", param.key, url.QueryEscape(param.value))
		}
	}
	s += fmt.Sprintf("app_key=%s", APPKEY)

	data := []byte(s)
	dataSum := md5.Sum(data)
	s = fmt.Sprintf("%x", dataSum)

	s = strings.ToUpper(s)
	return s
}

func GetRequestData(imgPath string) (RequestData, error) {
	fileData, err := GetByteFromFile(imgPath)
	if err != nil {
		return RequestData{}, err
	}

	req := RequestData{
		AppId: APPID,
		TimeStamp: int(time.Now().Unix()),
		NonceStr: "123456",
		Sign: "",
		Image: fileData,
	}
	var params []Param
	params = append(params, Param{key:"app_id", value: strconv.Itoa(req.AppId)})
	params = append(params, Param{key:"time_stamp", value: strconv.Itoa(req.TimeStamp)})
	params = append(params, Param{key:"nonce_str", value: req.NonceStr})
	params = append(params, Param{key:"sign", value: req.Sign})
	params = append(params, Param{key:"image", value: req.Image})
	req.Sign = GetSign(params)
	req.Params = ""
	for _, param := range params {
		if param.key == "sign" {
			req.Params += fmt.Sprintf("sign=%s&", req.Sign)
		} else if len(param.value) > 0 {
			req.Params += fmt.Sprintf("%s=%s&", param.key, url.QueryEscape(param.value))
		}
	}
	if len(req.Params) > 1{
		req.Params = req.Params[0:len(req.Params) - 1]
	}
	return req, nil
}

func GetByteFromFile(filePath string) (string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		return "", err
	}
	defer file.Close()

	pic, err := ioutil.ReadAll(file)
	if err != nil {
		return "", err
	}

	return base64.StdEncoding.EncodeToString(pic), nil
}