我怎样才能将我的JS对象转换为FormData?
我这样做的原因是，我有一个用~100个表单字段值构造的对象。
var item = {
description: 'Some Item',
price : '0.00',
srate : '0.00',
color : 'red',
...
...
}
现在我被要求将上传文件功能添加到我的表单，当然，通过JSON是不可能的，所以我计划移动到FormData。那么有什么方法可以将我的JS对象转换为FormData呢?
当前回答
下面是一个非常简单的TypeScript实现，基于@Vladimir Novopashin和@developer033的回答。打印稿操场
type Serializeable =
| string
| number
| boolean
| null
| Date
| File
| { [x: string | number]: Serializeable }
| Array<Serializeable>;
function serialize(
data: Serializeable,
parentKey = '',
formData: FormData = new FormData()
): FormData {
if ( typeof data === 'string') {
formData.append(parentKey, data);
} else if ( typeof data === 'number') {
formData.append(parentKey, data.toString());
} else if ( typeof data === 'boolean') {
formData.append(parentKey, data ? 'true' : 'false');
} else if (data === null) {
formData.append(parentKey, 'null');
} else if (data instanceof Date) {
formData.append(parentKey, data.toISOString());
} else if (data instanceof File) {
formData.append(parentKey, data);
} else {
// Arrays and objects
Object.entries(data).forEach((entry: [string | number, Serializeable]) => {
const [key, value] = entry;
serialize(value, parentKey ? `${parentKey}[${key}]` : key.toString(), formData);
});
}
return formData;
}
其他回答
抱歉这么晚才回答，我一直在纠结这个问题，因为Angular 2目前不支持文件上传。方法是用FormData发送一个XMLHttpRequest。我创建了一个函数来做这个。我用的是Typescript。要将其转换为Javascript只需删除数据类型声明。
/**
* Transforms the json data into form data.
*
* Example:
*
* Input:
*
* fd = new FormData();
* dob = {
* name: 'phone',
* photos: ['myphoto.jpg', 'myotherphoto.png'],
* price: '615.99',
* color: {
* front: 'red',
* back: 'blue'
* },
* buttons: ['power', 'volup', 'voldown'],
* cameras: [{
* name: 'front',
* res: '5Mpx'
* },{
* name: 'back',
* res: '10Mpx'
* }]
* };
* Say we want to replace 'myotherphoto.png'. We'll have this 'fob'.
* fob = {
* photos: [null, <File object>]
* };
* Say we want to wrap the object (Rails way):
* p = 'product';
*
* Output:
*
* 'fd' object updated. Now it will have these key-values "<key>, <value>":
*
* product[name], phone
* product[photos][], myphoto.jpg
* product[photos][], <File object>
* product[color][front], red
* product[color][back], blue
* product[buttons][], power
* product[buttons][], volup
* product[buttons][], voldown
* product[cameras][][name], front
* product[cameras][][res], 5Mpx
* product[cameras][][name], back
* product[cameras][][res], 10Mpx
*
* @param {FormData} fd FormData object where items will be appended to.
* @param {Object} dob Data object where items will be read from.
* @param {Object = null} fob File object where items will override dob's.
* @param {string = ''} p Prefix. Useful for wrapping objects and necessary for internal use (as this is a recursive method).
*/
append(fd: FormData, dob: Object, fob: Object = null, p: string = ''){
let apnd = this.append;
function isObj(dob, fob, p){
if(typeof dob == "object"){
if(!!dob && dob.constructor === Array){
p += '[]';
for(let i = 0; i < dob.length; i++){
let aux_fob = !!fob ? fob[i] : fob;
isObj(dob[i], aux_fob, p);
}
} else {
apnd(fd, dob, fob, p);
}
} else {
let value = !!fob ? fob : dob;
fd.append(p, value);
}
}
for(let prop in dob){
let aux_p = p == '' ? prop : `${p}[${prop}]`;
let aux_fob = !!fob ? fob[prop] : fob;
isObj(dob[prop], aux_fob, aux_p);
}
}
我可能有点晚了，但这就是我创建的将单个对象转换为FormData的方法。
function formData(formData, filesIgnore = []) {
let data = new FormData();
let files = filesIgnore;
Object.entries(formData).forEach(([key, value]) => {
if (typeof value === 'object' && !files.includes(key)) {
data.append(key, JSON.stringify(value) || null);
} else if (files.includes(key)) {
data.append(key, value[0] || null);
} else {
data.append(key, value || null);
}
})
return data;
}
它是如何工作的? 它将转换并返回所有属性，除了您在忽略列表中设置的File对象(第二个参数)。如果有人能告诉我一个更好的方法来确定这将有帮助!)变成一个json字符串使用json .stringify。然后在您的服务器上，您只需要将其转换回JSON对象。
例子:
let form = {
first_name: 'John',
last_name: 'Doe',
details: {
phone_number: 1234 5678 910,
address: '123 Some Street',
},
profile_picture: [object FileList] // set by your form file input. Currently only support 1 file per property.
}
function submit() {
let data = formData(form, ['profile_picture']);
axios.post('/url', data).then(res => {
console.log('object uploaded');
})
}
我仍然有点新的Http请求和JavaScript，所以任何反馈将高度赞赏!
下面是一个非常简单的TypeScript实现，基于@Vladimir Novopashin和@developer033的回答。打印稿操场
type Serializeable =
| string
| number
| boolean
| null
| Date
| File
| { [x: string | number]: Serializeable }
| Array<Serializeable>;
function serialize(
data: Serializeable,
parentKey = '',
formData: FormData = new FormData()
): FormData {
if ( typeof data === 'string') {
formData.append(parentKey, data);
} else if ( typeof data === 'number') {
formData.append(parentKey, data.toString());
} else if ( typeof data === 'boolean') {
formData.append(parentKey, data ? 'true' : 'false');
} else if (data === null) {
formData.append(parentKey, 'null');
} else if (data instanceof Date) {
formData.append(parentKey, data.toISOString());
} else if (data instanceof File) {
formData.append(parentKey, data);
} else {
// Arrays and objects
Object.entries(data).forEach((entry: [string | number, Serializeable]) => {
const [key, value] = entry;
serialize(value, parentKey ? `${parentKey}[${key}]` : key.toString(), formData);
});
}
return formData;
}
在我的例子中，我的对象也有属性，即文件数组。因为它们是二进制的，所以应该以不同的方式处理——索引不需要是键的一部分。所以我修改了@Vladimir Novopashin和@developer033的答案:
export function convertToFormData(data, formData, parentKey) {
if(data === null || data === undefined) return null;
formData = formData || new FormData();
if (typeof data === 'object' && !(data instanceof Date) && !(data instanceof File)) {
Object.keys(data).forEach(key =>
convertToFormData(data[key], formData, (!parentKey ? key : (data[key] instanceof File ? parentKey : `${parentKey}[${key}]`)))
);
} else {
formData.append(parentKey, data);
}
return formData;
}
我有一个场景，在构造表单数据时，嵌套的JSON必须以线性方式序列化，因为这是服务器期望值的方式。所以，我写了一个小的递归函数来翻译JSON，就像这样:
{
"orderPrice":"11",
"cardNumber":"************1234",
"id":"8796191359018",
"accountHolderName":"Raj Pawan",
"expiryMonth":"02",
"expiryYear":"2019",
"issueNumber":null,
"billingAddress":{
"city":"Wonderland",
"code":"8796682911767",
"firstname":"Raj Pawan",
"lastname":"Gumdal",
"line1":"Addr Line 1",
"line2":null,
"state":"US-AS",
"region":{
"isocode":"US-AS"
},
"zip":"76767-6776"
}
}
变成这样:
{
"orderPrice":"11",
"cardNumber":"************1234",
"id":"8796191359018",
"accountHolderName":"Raj Pawan",
"expiryMonth":"02",
"expiryYear":"2019",
"issueNumber":null,
"billingAddress.city":"Wonderland",
"billingAddress.code":"8796682911767",
"billingAddress.firstname":"Raj Pawan",
"billingAddress.lastname":"Gumdal",
"billingAddress.line1":"Addr Line 1",
"billingAddress.line2":null,
"billingAddress.state":"US-AS",
"billingAddress.region.isocode":"US-AS",
"billingAddress.zip":"76767-6776"
}
服务器将接受这种转换格式的表单数据。
函数如下:
function jsonToFormData (inJSON, inTestJSON, inFormData, parentKey) {
// http://stackoverflow.com/a/22783314/260665
// Raj: Converts any nested JSON to formData.
var form_data = inFormData || new FormData();
var testJSON = inTestJSON || {};
for ( var key in inJSON ) {
// 1. If it is a recursion, then key has to be constructed like "parent.child" where parent JSON contains a child JSON
// 2. Perform append data only if the value for key is not a JSON, recurse otherwise!
var constructedKey = key;
if (parentKey) {
constructedKey = parentKey + "." + key;
}
var value = inJSON[key];
if (value && value.constructor === {}.constructor) {
// This is a JSON, we now need to recurse!
jsonToFormData (value, testJSON, form_data, constructedKey);
} else {
form_data.append(constructedKey, inJSON[key]);
testJSON[constructedKey] = inJSON[key];
}
}
return form_data;
}
调用:
var testJSON = {};
var form_data = jsonToFormData (jsonForPost, testJSON);
我使用testJSON只是为了查看转换后的结果，因为我无法提取form_data的内容。AJAX post call:
$.ajax({
type: "POST",
url: somePostURL,
data: form_data,
processData : false,
contentType : false,
success: function (data) {
},
error: function (e) {
}
});
