英文:
Parse javascript Blob in golang
问题
在Go语言中，你可以使用r.ParseMultipartForm()方法来读取通过Ajax和FormData发送的表单数据，该方法会将表单请求数据填充到Form映射中。
func form(w http.ResponseWriter, r *http.Request) {
r.ParseMultipartForm(500)
fmt.Fprintf(w, "This is the value of %+v", r.Form)
}
然而，我还没有找到一种解析Blob的方法。上面的代码在我发送Blob而不是表单时返回一个空映射。也就是说，当我发送以下内容时：
var blob = new Blob([JSON.stringify(someJavascriptObj)]);
//XHR initialization, etc. etc.
xhr.send(blob);
上述Go代码不起作用。但是，当我发送以下内容时：
var form = new FormData(document.querySelector("form"));
//...
xhr.send(form);
我可以正常读取表单数据。
英文:
In Go, you can read a form sent using Ajax and FormData using r.ParseMultipartForm(), which populates the Form map with form request data.
func form(w http.ResponseWriter, r *http.Request) {
r.ParseMultipartForm(500) //
fmt.Fprintf(w, "This is the value of %+v", r.Form)
}
However, I haven't found a method to parse Blobs. The above code returns an empty map whenever instead of sending a form, I send a Blob. That is, when I send this:
var blob = new Blob([JSON.stringify(someJavascriptObj)]);
//XHR initialization, etc. etc.
xhr.send(blob);
the Go code above doesn't work. Now, when I send this:
var form = new FormData(document.querySelector("form"));
//...
xhr.send(form);
I can read form data without problems.
答案1
得分: 1
r.ParseMultipartForm(500)
这里可能返回了一个错误？尝试捕获错误：
if err := r.ParseMultipartForm(500); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
此外，考虑将500字节的内存限制提高，因为较大的数据块将被写入临时文件。
英文:
r.ParseMultipartForm(500)
Perhaps an error is being returned here? Try capturing the error:
if err := r.ParseMultipartForm(500); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
}
Also, consider raising the 500 byte memory limit as larger blobs will be written to temporary files.
答案2
得分: 1
我认为JavaScript将blob视为文件，所以你可以在r.MultipartForm.File中查找它，获取文件头，打开它，读取、解码和解析它。
例如，尝试以下代码：
r.ParseMultipartForm(500)
fmt.Fprintf(w, "This is the value of %+v", *r.MultipartForm.File)
}
请注意，这是一个示例代码，具体实现可能会有所不同。
英文:
I think javascript treats blob as file, so your can look it in r.MultipartForm.File, get file header, open it, read, decode and parse.
Try for example
r.ParseMultipartForm(500)
fmt.Fprintf(w, "This is the value of %+v", *r.MultipartForm.File)
}
答案3
得分: 0
我假设JavaScript的Blob是一个十六进制字符串，最终可以转换为Go中JSON的标准类型[]byte。
// 一旦你获取到Blob
blobString := 7b22666f6f223a205b22626172222c202262617a222c2039395d7d
b, _ := hex.DecodeString(blobString)
json := string(b)
fmt.Println(json) // 输出 {"foo": ["bar", "baz", 99]}
如果你的Blob来自JavaScript，你可能需要查看encoding/hex和encoding/binary包，将其解码为Go中的[]byte类型。
英文:
I presume Javascript's Blob is a hex string which can eventually be converted to []byte, which is a standard type for JSON in Go.
// Once you get the blob
blobString := `7b22666f6f223a205b22626172222c202262617a222c2039395d7d`
b, _ := hex.DecodeString(blobString)
json := string(b)
fmt.Println(json) // prints out {"foo": ["bar", "baz", 99]}
You might want to look into encoding/hex and encoding/binary packages to decode your blob acquired from Javascript to type []byte in Go, if it's not already.
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