HTTP的文件上传
在HTTP相关开发期间，往往会涉及到上传文件，其中会涉及multipart/form-data。
而官方的HTTP和multipart/form-data相关的协议有：
对于用HTTP的multipart/form-data实现文件上传：
- 既有合适的如Postman等工具方便去调试
- 也有iOS中Alamofire等库很好的支持
- （如果清楚协议详情）也可以自己手动写代码拼接出
multipart/form-data所需要的字段和内容去实现文件上传
下面就来详细介绍这方面的内容。
iOS中Alamofire支持文件上传的MultipartFormData
可以基本实现文件上传的iOS的Alamofire的代码：
func uploadImageData(imageData:NSData){
dispatchBackground_async({
gLog.verbose("imageData.length=\(imageData.length)")
self.pleaseWait()
var curHeader = Dictionary<String, String>()
curHeader["authenticate"] = "token " + gCurUserItem.accessToken
gLog.verbose("curHeader=\(curHeader)")
let curDate = NSDate()
let name = "file"
let filename = curDate.toString("yyyyMMdd_hhmmss") + ".jpg"
gLog.verbose("name=\(name), filename=\(filename)")
//uploadImageData > name=file, filename=20160625_085958.jpg
Alamofire.upload(
.POST,
ServerApi.uploadFileUrl(gCurUserItem.id),
headers: curHeader,
multipartFormData: {multipartFormData in
multipartFormData.appendBodyPart(
data: imageData,
name: name,
fileName: filename,
mimeType: "image/jpeg"
)
},
encodingCompletion: { encodingResult in
gLog.verbose("encodingResult=\(encodingResult)")
/*
encodingResult=Success($ curl -i \
-X POST \
-H "User-Agent: Xxx App/com.xxx.YyyApp (2016.6.24; OS ban ben 9.3(ban hao 13E230))" \
-H "authenticate: token zzzzzz" \
-H "Content-Type: multipart/form-data; boundary=alamofire.boundary.5fd5efc56016a4df" \
-H "Accept-Encoding: gzip;q=1.0, compress;q=0.5" \
-H "Accept-Language: en-US;q=1.0, zh-Hans-US;q=0.9" \
"http://192.168.1.102:8080/app/user/10000010/upload", false, nil)
encodingResult=Success($ curl -i \
-X POST \
-H "User-Agent: Xxx App/com.xxx.YyyApp (2016.6.24; OS ban ben 9.3(ban hao 13E230))" \
-H "authenticate: token zzzzzz" \
-H "Content-Type: multipart/form-data; boundary=alamofire.boundary.01fc8db6b551cd51" \
-H "Accept-Encoding: gzip;q=1.0, compress;q=0.5" \
-H "Accept-Language: en-US;q=1.0, zh-Hans-US;q=0.9" \
"http://xxx.yyy.cn/app/user/10000010/upload", false, nil)
*/
switch encodingResult {
//case .Success(let uploadRequest, streamingFromDisk, streamFileURL):
case .Success(let uploadRequest, _, _):
// gLog.verbose("uploadRequest=\(uploadRequest), streamingFromDisk=\(streamingFromDisk), streamFileURL=\(streamFileURL)")
gLog.verbose("uploadRequest=\(uploadRequest)")
//upload=POST http://192.168.1.102:8080/app/user/10000010/upload
//uploadRequest=POST http://xxx.yyy.cn/app/user/10000010/upload
uploadRequest.responseJSON(completionHandler:
{ response in
gLog.verbose("response=\(response)")
/*
response=SUCCESS: {
code = 200;
data = {
created = 1466850689624;
id = 1000001020160625103129624;
location = "<null>";
name = "image.jpg";
owner = "<null>";
uploader = 10000010;
};
message = ok;
}
response=SUCCESS: {
errors = (
"The request body may not be null",
"The request body may not be null"
);
}
response=SUCCESS: {
code = 200;
data = {
created = 1466859610413;
id = 1000001020160625130010413;
location = "<null>";
name = "20160625_085958.jpg";
owner = "<null>";
uploader = 10000010;
};
message = ok;
}
*/
switch response.result {
case .Success(let value):
let valueJson = JSON(value)
gLog.verbose("\(valueJson)")
/*
{
"message" : "ok",
"code" : 200,
"data" : {
"name" : "image.jpg",
"id" : "1000001020160625103129624",
"uploader" : 10000010,
"location" : null,
"created" : 1466850689624,
"owner" : null
}
}
*/
let statusCode = valueJson["code"].int ?? 0
if statusCode == 200 {
let dataObj = valueJson["data"].object
let dataJson:JSON = JSON(dataObj)
self.uploadAttachmentsHandler(Alamofire.Result.Success(dataJson))
gLog.verbose("dataJson=\(dataJson)")
} else {
self.noticeError("上传附件出错", autoClear: true, autoClearTime: 1)
let message = valueJson["message"].string ?? ""
let messageStrArr = message.splitToStrArr("|")
var messageStr:String = message
var subCode:Int = 0
if messageStrArr.count > 1 {
messageStr = messageStrArr[0]
subCode = Int(messageStrArr[1]) ?? 0
}
let error:NSError = NSError(domain: HttpErrorDomain, code: statusCode, userInfo: [
"message" : messageStr,
"code" : statusCode,
"subCode" : subCode,
])
self.uploadAttachmentsHandler(Alamofire.Result.Failure(error))
}
case .Failure(let error):
gLog.verbose("error=\(error)")
self.uploadAttachmentsHandler(Alamofire.Result.Failure(error))
}
})
case .Failure(let encodingError):
gLog.error("上传附件失败\(encodingError)")
}
}
)
})
}
详见：
［已解决］Alamofire中multipartFormData中的name和filename到底应该是什么值
Postman中可以方便的调试文件上传
当然，如果后台设计的不是很规范，则可能导致，即使传入了标准的参数设置：
- POST xxx/xxx/upload
- Headers
Authorization: Bearer 6c9f198878cb42e6aad83fecbb598d10_8a9bfdab5a21ca27015a21d72fb20000Content-Type: multipart/form-data;boundary=any_random_valueAccept: application/json
却仍可能会返回错误HTTP 415 Unsupported Media Type
详见：
【已解决】Mac中Postman去POST实现文件上传时出错：HTTP 415 Unsupported Media Type – 在路上
但是本身Postman对于文件上传的支持，还是很方便很好用的。
C#中如何手动裸写multipart/form-data的文件上传
之前也曾折腾过，自己用C#代码拼凑出multipart/form-data所需要的内容的格式。
如此折腾后，算是对于multipart/form-data有了更深入的认识。
详见：