英文:
How to send an string to server using fetch API
问题
我正在使用fetch API向我的Go服务器发起POST请求...
fetch('http://localhost:8080', {method:'POST',headers: {'Accept': 'application/json','Content-Type': 'application/json'},body: JSON.stringify({image:"hello"})}).then((response) => response.json()).then((responseJson) => {console.log("response");}).catch(function(error) {console.log(error);})
在我的Go服务器上，我正在接收这个POST请求...
type test_struct struct {Test string}func GetImage(rw http.ResponseWriter, req *http.Request, _ httprouter.Params) {var t test_structif req.Body == nil {http.Error(rw, "Please send a request body", 400)return}err := json.NewDecoder(req.Body).Decode(&t)fmt.Println(req.Body)if err != nil {http.Error(rw, err.Error(), 400)return}fmt.Println(t.Test);}
POST请求已经发送。我知道这一点，因为fmt.Println(t.Test)在控制台上打印了一个空行。
fmt.Println(req.Body)在控制台上给出了<nil>。
我只收到来自fetch API的错误消息。它在控制台上打印了以下错误...
SyntaxError: Unexpected end of input
这是来自.catch声明的错误。
简而言之，我如何在服务器上接收到这个字符串？
英文:
I am using the fetch API to make a POST request to my server written in Go...
fetch('http://localhost:8080', {method:'POST',headers: {'Accept': 'application/json','Content-Type': 'application/json'},body: JSON.stringify({image:"hello"})}).then((response) => response.json()).then((responseJson) => {console.log("response");}).catch(function(error) {console.log(error);})
On my Go server I am receiving the POST...
type test_struct struct {Test string}func GetImage(rw http.ResponseWriter, req *http.Request, _ httprouter.Params) {var t test_structif req.Body == nil {http.Error(rw, "Please send a request body", 400)return}err := json.NewDecoder(req.Body).Decode(&t)fmt.Println(req.Body)if err != nil {http.Error(rw, err.Error(), 400)return}fmt.Println(t.Test);}
The POST request is made. I know this because fmt.Println(t.Test) is printing a blank line to the console.
fmt.Println(req.Body) gives me <nil> in the console.
The only error message I get is from the fetch API. It prints to the console the following error...
SyntaxError: Unexpected end of input
this is coming from the .catch declaration.
In short, how can I receive the string on the server?
答案1
得分: 3
当你解码req.Body时，你不能再次读取请求体，因为它已经读取了缓冲区，所以你会收到SyntaxError: Unexpected end of input的错误消息。如果你想使用req.Body的值，你必须将req.Body的内容保存在一个变量中，类似这样的方式。
buf, err := ioutil.ReadAll(r.Body)// 在读取r.Body时检查错误reader := bytes.NewReader(buf)err = json.NewDecoder(reader).Decode(&t)fmt.Println(string(buf))if err != nil {http.Error(rw, err.Error(), 400)return}
另外，你的JSON格式是{"image":"hello"}，所以你的结构体应该是：
type test_struct struct {Test string `json:"image"`}
如果你想将image的值映射到Test字段。
英文:
When you decode req.Body, you can't read again the request body, because it's already read the buffer, for that reason you're getting the message SyntaxError: Unexpected end of input. If you want to use the value on req.Body, you must to save the content of req.Body in a variable, something like this.
buf, err := ioutil.ReadAll(r.Body)// check err for errors when you read r.Bodyreader := bytes.NewReader(buf)err = json.NewDecoder(reader).Decode(&t)fmt.Println(string(buf))if err != nil {http.Error(rw, err.Error(), 400)return}
Also, your JSON is like {"image":"hello"}, so your struct should be:
type test_struct struct {Test string `json:"image"`}
If you want to map the image value into Test
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