// Filter the request data to get the file binary data.
// Here is an algorithm logic to filter the data. There
// will be a lot of words to say before we talk about
// the algorithm(Maybe a small book). So I just open the
// source here but omit the explanation in details.
private void FilterFileDataFromBodyEntity(byte[] data)
{
if (data == null)
{
return;
}
if (draft != null)
{
byte[] temp = BinaryHelper.Combine(draft,
BinaryHelper.Copy(data, 0, _boundary.Length));
int entity_st = BinaryHelper.SequenceIndexOf(temp, _boundary, 0);
int entity_ed = BinaryHelper.SequenceIndexOf(temp, _boundary,
entity_st + _boundary.Length + 2);
if (isFile && !isFinished)
{
if (entity_st == 0)
{
int header_st = entity_st + _boundary.Length + 2;
int header_ed = BinaryHelper.SequenceIndexOf(temp,
_doubleBackSpace, header_st);
int body_st = header_ed + 4;
if (entity_ed == -1)
{
AppendToLastEntity(BinaryHelper.SubData(draft, body_st));
draft = null;
}
else
{
AppendToLastEntity(BinaryHelper.SubData(draft,
body_st, entity_ed - body_st - 2));
isFinished = true;
isFile = false;
draft = BinaryHelper.SubData(draft, entity_ed);
}
}
else
{
AppendToLastEntity(draft);
draft = null;
}
}
// When need append new data, combine the two
// binary array into one.
data = BinaryHelper.Combine(draft, data);
draft = null;
}
while (true)
{
// find the boundary
int entity_st = BinaryHelper.SequenceIndexOf(data, _boundary, 0);
// if the current loaded data contain the boundary
if (entity_st > -1)
{
if (isFile && !isFinished)
{
AppendToLastEntity(BinaryHelper.SubData(data, 0,
entity_st - 2));
data = BinaryHelper.SubData(data, entity_st);
isFile = false;
isFinished = true;
continue;
}
int entity_ed = BinaryHelper.SequenceIndexOf(data, _boundary,
entity_st + _boundary.Length + 2);
int header_st = entity_st + _boundary.Length + 2;
int header_ed = BinaryHelper.SequenceIndexOf(data,
_doubleBackSpace, header_st);
int body_st = header_ed + 4;
if (body_st < 4)
{
// If the header in the entity is not complete, then
// set the draft as the data, and dump out the function
// to ask for more data.
draft = data;
return;
}
else
{
// If the header in the entity is complete
if (!isFile && isFinished)
{
// Encoding the data in the header of the entity
string headerInEntity = ASCIIEncoding.UTF8.GetString(
BinaryHelper.SubData(data, header_st, header_ed - header_st));
// If it is a file entity, the header contain the keyword:"filename".
if (headerInEntity.IndexOf("filename") > -1)
{
// Use Regular Expression to get the meta key values from
// the header of the entity.
Regex detailsReg =
new Regex("Content-Disposition: form-data; name=\"([^\"]*)\";" +
" filename=\"([^\"]*)\"Content-Type: ([^\"]*)");
Match regMatch =
detailsReg.Match(headerInEntity.Replace("\r\n", ""));
string controlName = regMatch.Groups[1].Value;
string clientPath = regMatch.Groups[2].Value;
string contentType = regMatch.Groups[3].Value;
if (string.IsNullOrEmpty(clientPath))
{
isFile = false;
}
else
{
isFile = true;
// Create a new instance for the file entity
UploadFile up = new UploadFile(clientPath, contentType);
FilterResult.Add(up);
isFinished = false;
}
}
else
{
isFile = false;
}
}
}
if (entity_ed > -1)
{
// If we can find another boundary after the first boundary,
// that means the entity block is ended there.
// Only if it is a file entity we need to get the data
// in the body of the entity
if (isFile)
{
AppendToLastEntity(BinaryHelper.SubData(data,
body_st, entity_ed - body_st - 2));
isFinished = true;
isFile = false;
}
// Remove the current processed entity data
// and loop for the next one.
data = BinaryHelper.SubData(data, entity_ed);
if (BinaryHelper.Equals(data, _endTag))
{
data = null;
draft = null;
return;
}
continue;
}
else
{
// If we can't find the end mark, we have to
// move the data to the draft and
// ask for new data to append.
draft = data;
return;
}
}
else
{
// If we can't find any mark of the boundary,
// we have to move the data to the draft and
// ask for new data to append.
draft = data;
return;
}
}
}
// 过滤请求数据来获取文件的二进制数据.
// 这里是过滤数据的算法逻辑.
// 在我们讲到算法之前将会有很多内容要
// 讲（可能要一本书）.所以我只在这里开
// 个头，但是忽略详细的解释.
private void FilterFileDataFromBodyEntity(byte[] data)
{
if (data == null)
{
return;
}
if (draft != null)
{
byte[] temp = BinaryHelper.Combine(draft,
BinaryHelper.Copy(data, 0, _boundary.Length));
int entity_st = BinaryHelper.SequenceIndexOf(temp, _boundary, 0);
int entity_ed = BinaryHelper.SequenceIndexOf(temp, _boundary,
entity_st + _boundary.Length + 2);
if (isFile && !isFinished)
{
if (entity_st == 0)
{
int header_st = entity_st + _boundary.Length + 2;
int header_ed = BinaryHelper.SequenceIndexOf(temp,
_doubleBackSpace, header_st);
int body_st = header_ed + 4;
if (entity_ed == -1)
{
AppendToLastEntity(BinaryHelper.SubData(draft, body_st));
draft = null;
}
else
{
AppendToLastEntity(BinaryHelper.SubData(draft,
body_st, entity_ed - body_st - 2));
isFinished = true;
isFile = false;
draft = BinaryHelper.SubData(draft, entity_ed);
}
}
else
{
AppendToLastEntity(draft);
draft = null;
}
}
// 当需要添加新数据时，
// 把这两个二进制数组合并成一个.
data = BinaryHelper.Combine(draft, data);
draft = null;
}
while (true)
{
// 找到边界
int entity_st = BinaryHelper.SequenceIndexOf(data, _boundary, 0);
// 如果当前加载的数据包含边界
if (entity_st > -1)
{
if (isFile && !isFinished)
{
AppendToLastEntity(BinaryHelper.SubData(data, 0,
entity_st - 2));
data = BinaryHelper.SubData(data, entity_st);
isFile = false;
isFinished = true;
continue;
}
int entity_ed = BinaryHelper.SequenceIndexOf(data, _boundary,
entity_st + _boundary.Length + 2);
int header_st = entity_st + _boundary.Length + 2;
int header_ed = BinaryHelper.SequenceIndexOf(data,
_doubleBackSpace, header_st);
int body_st = header_ed + 4;
if (body_st < 4)
{
// 如果实体的头部不完整，
// 设置这个实体作为数据，
// 卸载掉函数来请求更多的数据.
draft = data;
return;
}
else
{
// 如果实体的头部完整
if (!isFile && isFinished)
{
// 把实体头部的数据转换为UTF8编码
string headerInEntity = ASCIIEncoding.UTF8.GetString(
BinaryHelper.SubData(data, header_st, header_ed - header_st));
// 如果这是一个文件实体，头部包会含关键字："filename".
if (headerInEntity.IndexOf("filename") > -1)
{
// 在实体的头部使用正则表达式来
// 获取元数据的关键字值.
Regex detailsReg =
new Regex("Content-Disposition: form-data; name=\"([^\"]*)\";" +
" filename=\"([^\"]*)\"Content-Type: ([^\"]*)");
Match regMatch =
detailsReg.Match(headerInEntity.Replace("\r\n", ""));
string controlName = regMatch.Groups[1].Value;
string clientPath = regMatch.Groups[2].Value;
string contentType = regMatch.Groups[3].Value;
if (string.IsNullOrEmpty(clientPath))
{
isFile = false;
}
else
{
isFile = true;
// 为文件实体创建一个新的实例
UploadFile up = new UploadFile(clientPath, contentType);
FilterResult.Add(up);
isFinished = false;
}
}
else
{
isFile = false;
}
}
}
if (entity_ed > -1)
{
// 如果我们在第一个边界之后又发现另一边界，
// 那表示实体块在那里结束了.
// 只是文件实体的时候，我们才需要在实体的
// 主体里获取数据.
if (isFile)
{
AppendToLastEntity(BinaryHelper.SubData(data,
body_st, entity_ed - body_st - 2));
isFinished = true;
isFile = false;
}
// 移除当前的实体处理数据并且
// 循环到下一个数据.
data = BinaryHelper.SubData(data, entity_ed);
if (BinaryHelper.Equals(data, _endTag))
{
data = null;
draft = null;
return;
}
continue;
}
else
{
// 如果我们不能找到结束标记,我们
// 必须要把这些数据移到草稿并
// 请求添加新数据.
draft = data;
return;
}
}
else
{
// 如果我们不能找到结束标记,我们
// 必须要把这些数据移到草稿并
// 请求添加新数据.
draft = data;
return;
}
}
}
private void context_BeginRequest(object sender, EventArgs e)
{
HttpApplication app = sender as HttpApplication;
HttpContext context = app.Context;
// We need the HttpWorkerRequest of the current context to
// process the request data. For more details about HttpWorkerRequest,
// please follow the Readme file in the root directory.
IServiceProvider provider = (IServiceProvider)context;
System.Web.HttpWorkerRequest request =
(HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
// Get the content type of the current request.
string contentType =
request.GetKnownRequestHeader(
System.Web.HttpWorkerRequest.HeaderContentType);
// If we could not get the content type, then skip out the module
if (contentType == null)
{
return;
}
// If the content type is not multipart/form-data,
// means that there is no file upload request
// then skip out the moudle
if (contentType.IndexOf("multipart/form-data") == -1)
{
return;
}
string boundary = contentType.Substring(contentType.IndexOf("boundary=") + 9);
// Get the content length of the current request
long contentLength = Convert.ToInt64(
request.GetKnownRequestHeader(
HttpWorkerRequest.HeaderContentLength));
// Get the data of the portion of the HTTP request body
// that has currently been read.
// This is the first step for us to store the upload file.
byte[] data = request.GetPreloadedEntityBody();
// Create an instance of the manager class which
// help to filter the request data.
FileUploadDataManager storeManager =
new FileUploadDataManager(boundary);
// Append the preloaded data.
storeManager.AppendData(data);
UploadStatus status = null;
if (context.Cache[_cacheContainer] == null)
{
//Initialize the UploadStatus which used to
//store the status for the client.
status = new UploadStatus(
context, // Send the current context to the status
// which will be used for the events.
contentLength // Initialize the file length.
);
// Bind a event when update the status.
status.OnDataChanged +=
new UploadStatusEventHandler(status_OnDataChanged);
}
else
{
status = context.Cache[_cacheContainer] as UploadStatus;
if (status.IsFinished)
{
return;
}
}
// Set the first read data length to the status class.
if (data != null)
{
status.UpdateLoadedLength(data.Length);
}
// Get the length of the left request data.
long leftdata = status.ContentLength - status.LoadedLength;
// Define a custom buffer length
int customBufferLength = Convert.ToInt32(Math.Ceiling((double)contentLength / 16));
if (customBufferLength < 1024)
{
customBufferLength = 1024;
}
while (!request.IsEntireEntityBodyIsPreloaded() && leftdata > 0)
{
// Check if user abort the upload, then close the connection
if (status.Aborted)
{
// Delete the cached files.
foreach (UploadFile file in storeManager.FilterResult)
{
file.ClearCache();
}
request.CloseConnection();
return;
}
// If the length the remained request data
// is less than the buffer length,
// then set the buffer length as the remained data length.
if (leftdata < customBufferLength)
{
customBufferLength = (int)leftdata;
}
// Read a custom buffer length of the request data
data = new byte[customBufferLength];
int redlen = request.ReadEntityBody(data, customBufferLength);
if (customBufferLength > redlen)
{
data = BinaryHelper.SubData(data, 0, redlen);
}
// Append the left data.
storeManager.AppendData(data);
// Add the buffer length to the status to update the upload status
status.UpdateLoadedLength(redlen);
leftdata -= redlen;
}
// After all the data has been read,
// save the uploaded files.
foreach (UploadFile file in storeManager.FilterResult)
{
file.Save(null);
}
}
private void context_BeginRequest(object sender, EventArgs e)
{
HttpApplication app = sender as HttpApplication;
HttpContext context = app.Context;
// 我们需要HttpWorkerRequest的当前内容来处理请求数据.
// 要想知道HttpWorkerRequest更多更详细的内容,
// 请参考根目录下的Readme文件.
IServiceProvider provider = (IServiceProvider)context;
System.Web.HttpWorkerRequest request =
(HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
// 获取当前请求的内容类型.
string contentType =
request.GetKnownRequestHeader(
System.Web.HttpWorkerRequest.HeaderContentType);
// 如果我们不能获取内容类型，跳过这个模块.
if (contentType == null)
{
return;
}
// 如果内容类型不是multipart/form-data,
// 意味着没有上传请求，
// 就可以跳过这个模块.
if (contentType.IndexOf("multipart/form-data") == -1)
{
return;
}
string boundary = contentType.Substring(contentType.IndexOf("boundary=") + 9);
// 获取当前请求的内容长度.
long contentLength = Convert.ToInt64(
request.GetKnownRequestHeader(
HttpWorkerRequest.HeaderContentLength));
// 获取HTTP请求主体的那些
// 当前已经被读取的数据.
// 这是我们存储上传文件的第一步.
byte[] data = request.GetPreloadedEntityBody();
// 创建一个管理类的实例可以
// 帮助过滤请求数据.
FileUploadDataManager storeManager =
new FileUploadDataManager(boundary);
// 添加预装载的数据.
storeManager.AppendData(data);
UploadStatus status = null;
if (context.Cache[_cacheContainer] == null)
{
//初始化UploadStatus，
//它被用来存储客户状态.
status = new UploadStatus(
context, // 把当前内容发送到status被事件使用
//
contentLength // 初始化文件长度.
);
// 当更新状态时绑定事件.
status.OnDataChanged +=
new UploadStatusEventHandler(status_OnDataChanged);
}
else
{
status = context.Cache[_cacheContainer] as UploadStatus;
if (status.IsFinished)
{
return;
}
}
// 把首先读到的数据长度设置到status class.
if (data != null)
{
status.UpdateLoadedLength(data.Length);
}
// 获取留下的请求数据的长度.
long leftdata = status.ContentLength - status.LoadedLength;
// 定义一个自定义的缓存区的长度
int customBufferLength = Convert.ToInt32(Math.Ceiling((double)contentLength / 16));
if (customBufferLength < 1024)
{
customBufferLength = 1024;
}
while (!request.IsEntireEntityBodyIsPreloaded() && leftdata > 0)
{
// 检查用户如果终止了上传，关闭连接.
if (status.Aborted)
{
// 删除缓存文件.
foreach (UploadFile file in storeManager.FilterResult)
{
file.ClearCache();
}
request.CloseConnection();
return;
}
// 如果剩下的请求数据小于缓
// 冲区的长度，把缓冲区的
// 长度设置成剩余数据的长度.
if (leftdata < customBufferLength)
{
customBufferLength = (int)leftdata;
}
// 读取自定义缓冲区的长度的请求数据
data = new byte[customBufferLength];
int redlen = request.ReadEntityBody(data, customBufferLength);
if (customBufferLength > redlen)
{
data = BinaryHelper.SubData(data, 0, redlen);
}
// 添加剩余数据.
storeManager.AppendData(data);
// 把缓冲区的长度添加到status来更新上传status.
status.UpdateLoadedLength(redlen);
leftdata -= redlen;
}
// 当所有的数据都被读取之后,
// 保存上传文件.
foreach (UploadFile file in storeManager.FilterResult)
{
file.Save(null);
}
}
