像许多其他新手一样，我正在关注 Manuel Kiessling 的“The Node Beginner Book”。
我们应该通过 Formidable 模块启用图像上传，不断将图像重命名为“test.png”并显示它。
这本书使用了路径/tmp/test.png，一切正常。但这不是相对路径，我的图像实际上保存在 Linux 的 tmp 文件夹中！
我在我的项目中创建了文件夹“tmp”，并试图在那里发生同样的事情，但我只看到一个错误！
ENOENT, open './tmp/test.png'
当我尝试路径时会发生同样的事情，tmp/test.png但有趣的是，当我将实际图像直接放入 tmp 文件夹并将其显示在我的页面上时，这两个路径都有效。所以语义/语法没有问题，或者..？
我的 requestHandler.js，其中重要的部分是上传和显示功能：
var querystring = require("querystring"),
fs = require("fs"),
formidable = require("formidable");
function start(response) {
console.log("Request handler 'start' was called.");
var body = '<html>' +
'<head>' +
'<meta http-equiv="Content-Type" content="text/html; ' +
'charset=UTF-8" />' +
'</head>' +
'<body>' +
'<form action="/upload" enctype="multipart/form-data" ' +
'method="post">' +
'<input type="file" name="upload" multiple="multiple">' +
'<input type="submit" value="Upload file" />' +
'</form>' +
'</body>' +
'</html>';
response.writeHead(200, {"Content-Type": "text/html"});
response.write(body);
response.end();
}
function upload(response, request) {
console.log("Request handler 'upload' was called.");
var form = new formidable.IncomingForm();
console.log("about to parse");
form.parse(request, function(error, fields, files) {
console.log("parsing done");
fs.rename(files.upload.path, "./tmp/test.png", function(err) {
if (err) {
console.log("Error Flynn");
fs.unlink("./tmp/test.png");
fs.rename(files.upload.path, "./tmp/test.png");
}
});
response.writeHead(200, {"Content-Type": "text/html"});
response.write("received image:<br/>");
response.write("<img src='/show' />");
response.end();
});
}
function show(response) {
console.log("Request handler 'show' was called.");
fs.readFile("./tmp/test.png", "binary", function(error, file) {
if(error) {
response.writeHead(500, {"Content-Type": "text/plain"});
response.write(error + "\n");
response.end();
}
else {
response.writeHead(200, {"Content-Type": "image/png"});
response.write(file, "binary");
response.end();
}
});
}
exports.start = start;
exports.upload = upload;
exports.show = show;
值得注意的是，我专门放在那里进行故障排除的“Error Flynn”错误消息确实被调用了，并且我放入文件夹中的文件被删除了！
这是日志：
Request for /upload received.
About to route a request for /upload
Request handler 'upload' was called.
about to parse
parsing done
Error Flynn
fs: missing callback Error: ENOENT, unlink './tmp/test.png'
fs: missing callback Error: EXDEV, rename '/tmp/upload_9bcb8afa8cd2f78ff52c294edd106965'
Request for /show received.
About to route a request for /show
Request handler 'show' was called.