Convert Error

接口请求出错的处理

默认的出错只针对HTTP请求失败，对于状态码为4xx，5xx的请求，需要针对各服务从响应数据中获取对应的出错信息，再转换为相应的自定义出错对象。在IPLocation这个服务，出错时响应的数据为`{"category": "出错类别", "message": "出错信息"}，因此增加自定义出错转换，代码如下：

package main

import (
    "crypto/tls"
    "fmt"
    "net/http"

    "github.com/vicanso/go-axios"
    "github.com/vicanso/hes"
)

var (
    ipLocationIns *axios.Instance
)

// convertResponseToError convert http response(4xx, 5xx) to error
func convertResponseToError(resp *axios.Response) error {
    if resp.Status >= 400 {
        he := &hes.Error{}
        err := resp.JSON(he)
        if err != nil {
            he.Message = string(resp.Data)
        }
        return he
    }
    return nil
}

func main() {
    _, err := ipLocationIns.Get("/ip-locations/json/123")
    fmt.Println(err)
}

func init() {
    headers := make(http.Header)
    headers.Set("Accept", "application/json")
    ipLocationIns = axios.NewInstance(&axios.InstanceConfig{
        Headers: headers,
        BaseURL: "https://ip.npmtrend.com",
        ResponseInterceptors: []axios.ResponseInterceptor{
            convertResponseToError,
        },
    })
}