我有一个前端 Canvas,我将其转换为 png 文件,我需要将其 POST 到第三方 vendor 的 api。它作为 base64 文件传回 Node 并对其进行解码,但是当我尝试上传时,它给出以下错误:
Problem processing POST request: no Content-Type specified
但是,我在 POST 调用中明确指定了内容类型。我的最终目标是将文件上传到我的 vendor 的 API。
以下是关键的前端方面:
var canvasImage = document.getElementById("c");
var img = canvas.toDataURL({
multiplier: canvasMultiplier
});
var fileTime = Date.now();
var myFileName = $scope.productCode + fileTime;
$scope.filenameForVendor = myFileName;
var filename = $scope.filenameForVendor;
$http.post('/postVendor', { filename: filename, file: img }).success(function (data) {
console.log("Uploaded to Vendor");
这是后端 POST:
app.post('/postVendor', function (req, res, next) {
var filename = req.body.filename;
var file = req.body.file;
fileBuffer = decodeBase64Image(file);
request({
url: "http://myvendorapi/ws/endpoint",
method: "POST",
headers: {
'contentType': fileBuffer.type
},
body: fileBuffer.data
}, function (error, response, body) {
console.log(response);
});
})
// Decode file for upload
function decodeBase64Image(dataString) {
var matches = dataString.match(/^data:([A-Za-z-+\/]+);base64,(.+)$/),
response = {};
if (matches.length !== 3) {
return new Error('Invalid input string');
}
response.type = matches[1];
response.data = new Buffer(matches[2], 'base64');
return response;
}
我可以在前端使用 AJAX 进行 POST,但由于 CORS 和 vendor 阻止了除服务器端对端点的调用之外的所有调用(并且它们没有 JSONP),我无法使用它。他们允许我的 IP 通过用于测试目的,因此只有我可以在我的机器上完成此工作:
var send = function (blob) {
var fileTime = Date.now();
var myFileName = $scope.productCode + fileTime;
$scope.filenameForVendor = myFileName;
var filename = $scope.filenameForVendor;
var formdata = new FormData();
formdata.append('File1', blob, filename);
$.ajax({
url: 'http://myvendorapi/ws/endpoint',
type: "POST",
data: formdata,
mimeType: "multipart/form-data",
processData: false,
contentType: false,
crossDomain: true,
success: function (result) {
console.log("Upload to Vendor complete!");
// rest of code here/including error close out
}
var bytes = atob(dataURL.split(',')[1])
var arr = new Uint8Array(bytes.length);
for (var i = 0; i < bytes.length; i++) {
arr[i] = bytes.charCodeAt(i);
}
send(new Blob([arr], { type: 'image/png' }));
更新:
我意识到 contentType 应该是“内容类型”。当我这样做时,它会产生一个未指定边界的错误,因为我正在尝试多部分表单数据(我做错了)。如何将formData传递给Node进行上传?
更新2:
根据提供的建议,我尝试使用 multer,但收到 ReferenceError:XMLHttpRequest 未定义。
客户端:
var fileTime = Date.now();
var myFileName = $scope.productCode + fileTime;
$scope.filenameForVendor = myFileName;
var filename = $scope.filenameForVendor;
var formdata = new FormData();
formdata.append('File1', blob, filename);
$http.post('/postVendor', formdata, { transformRequest: angular.identity, headers: { 'Content-Type': undefined } }).success(function (data) {
服务器端:
app.post('/postVendor', function (req, res, next) {
var request = new XMLHttpRequest();
request.open("POST", "http://myvendorapi.net/ws/endpoint");
request.send(formData);
})
最佳答案
为什么要对文件进行 Base64 编码?
您可以使用 FormData 将原始文件上传到您的 Node 并且您无需解码任何内容。
前端
...
var request = new XMLHttpRequest();
request.open('POST', 'http://node.js/method');
request.send(formData); // vanilla
--- 或 ---
...
$http.post('http://node.js/method', formData, {
transformRequest: angular.identity,
headers: {'Content-Type': undefined}
}); // angular
后端
只需安装 request .
...
var request = require('request');
app.post('/method', function (req, res, next) {
// if you just want to push request you don't need to parse anything
req.pipe(request('http://vendor.net')).pipe(res);
}) // express
关于javascript - Node/请求错误: "Processing POST Request: No Content-Type",我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34209986/