Node.js模拟浏览器文件上传示例

var path=require("path"); 
var fs=require("fs"); 
var http=require("http"); 

//post值payload 
var getfield=function(field, value) { 
return 'Content-Disposition: form-data; name="'+field+'"\r\n\r\n'+value+'\r\n'; 
} 

//文件payload 
var getfieldHead=function (field, filename) { 
var fileFieldHead='Content-Disposition: form-data; name="'+field+'"; filename="'+filename+'"\r\n'+'Content-Type: '+getMime(filename)+'\r\n\r\n'; 
return fileFieldHead; 
} 
//获取Mime 
var getMime=function (filename) { 
var mimes = { 
'.png': 'image/png', 
'.gif': 'image/gif', 
'.jpg': 'image/jpeg', 
'.jpeg': 'image/jpeg', 
'.js': 'appliction/json', 
'.torrent': 'application/octet-stream' 
}; 
var ext = path.extname(filename); 
var mime = mimes[ext]; 
mime=!!mime?mime:'application/octet-stream'; 
return mime; 
} 
//获取边界检查随机串 
var getBoundary=function() { 
var max = 9007199254740992; 
var dec = Math.random() * max; 
var hex = dec.toString(36); 
var boundary = hex; 
return boundary; 
} 
//获取boundary 
var getBoundaryBorder=function (boundary) { 
return '--'+boundary+'\r\n'; 
} 
//字段格式化 
function fieldPayload(opts) { 
var payload=[]; 
for(var id in opts.field){ 
payload.push(getfield(id,opts.field[id])); 
} 
payload.push(""); 
return payload.join(getBoundaryBorder(opts.boundary)); 
} 

//post数据 
function postRequest (opts) { 
filereadstream(opts,function (buffer) { 
var options=require('url').parse(opts.url); 
var Header={}; 
var h=getBoundaryBorder(opts.boundary); 
var e=fieldPayload(opts); 
var a=getfieldHead(opts.param,opts.file); 
var d="\r\n"+h; 
Header["Content-Length"]=Buffer.byteLength(h+e+a+d)+buffer.length; 
Header["Content-Type"]='multipart/form-data; boundary='+opts.boundary; 
options.headers=Header; 
options.method='POST'; 
var req=http.request(options,function(res){ 
var data=''; 
res.on('data', function (chunk) { 
data+=chunk; 
}); 
res.on('end', function () { 
console.log(res.statusCode) 
console.log(data); 
}); 
}); 
req.write(h+e+a);log.diy(h+e+a+buffer+d); 
req.write(buffer); 
req.end(d); 
}); 

} 
//读取文件 
function filereadstream(opts, fn) { 
var readstream = fs.createReadStream(opts.file,{flags:'r',encoding:null}); 
var chunks=[]; 
var length = 0; 
readstream.on('data', function(chunk) { 
length += chunk.length; 
chunks.push(chunk); 
}); 
readstream.on('end', function() { 
var buffer = new Buffer(length); 
for(var i = 0, pos = 0, size = chunks.length; i < size; i++) { 
chunks[i].copy(buffer, pos); 
pos += chunks[i].length; 
} 
fn(buffer); 
}); 
} 

//各类设置 
var opt={ 
"url":"http://xxxx.xx",//url 
"file":"00.jpg",//文件位置 
"param":"file",//文件上传字段名 
"field":{//其余post字段 
"client":"1", 
"title":"ok" 
}, 
"boundary":"----WebKitFormBoundary"+getBoundary() 
} 

postRequest(opt); 
/* 
------WebKitFormBoundaryuzKmkAovUuYsQ1Dt\r\n 

Content-Disposition: form-data; name="file"; filename="00.jpg"\r\n 
Content-Type: application/octet-stream 
\r\n 
\r\n +file\r\n 

------WebKitFormBoundaryuzKmkAovUuYsQ1Dt\r\n 

Content-Disposition: form-data; name="fieldName" 
\r\n 
\r\n +value\r\n 

------WebKitFormBoundaryuzKmkAovUuYsQ1Dt-- 
*/