使用C#实现网页内容保存为图片并生成压缩包
作者：初九之潜龙勿用
这篇文章主要为大家详细介绍了如何使用C#实现网页内容保存为图片并生成压缩包,文中的示例代码讲解详细,感兴趣的小伙伴可以跟随小编一起学习一下
应用场景
我们在一个求职简历打印的项目功能里，需要根据一定的查询条件，得到结果并批量导出指定格式的文件。导出的格式可能有多种，比如WORD格式、EXCEL格式、PDF格式等，实现方式是通过设置对应的模板进行输出，实际情况是，简历的内容是灵活设置的，没有固定的格式，模板数量是不固定的。
通过动态页面技术，可以实现简历配置后的网页内容输出，但制作对应的各种模板会遇到开发效率和服务跟进的问题。为了保障原样输出，折中而简单的方案就是将动态输出的页面转化为图片格式。
实现代码
创建一个 UrlToImage 类，创建实例的时候传递指定的 URL, 并调用 SaveToImageFile（string outputFilename）方法，该方法传递要输出的文件名参数即可即可。
调用示例代码如下：
string url = "https://" + Request.Url.Host + "/printResume.aspx";
UrlToImage uti = new UrlToImage(url);
bool irv = uti.SaveToImageFile(Request.PhysicalApplicationPath + "\\test.jpg");
if(bool==false){
Response.Write("save failed.");
Response.End();
}
类及实现代码如下：
public class UrlToImage
{
private Bitmap m_Bitmap;
private string m_Url;
private string m_FileName = string.Empty;
int initheight = 0;
public UrlToImage(string url)
{
// Without file
m_Url = url;
}
public UrlToImage(string url, string fileName)
{
// With file
m_Url = url;
m_FileName = fileName;
}
public Bitmap Generate()
{
// Thread
var m_thread = new Thread(_Generate);
m_thread.SetApartmentState(ApartmentState.STA);
m_thread.Start();
m_thread.Join();
return m_Bitmap;
}
public bool SaveToImageFile(string filename)
{
Bitmap bt=Generate();
if (bt == null)
{
return false;
}
bt.Save(filename);
return File.Exists(filename);
}
private void _Generate()
{
var browser = new WebBrowser { ScrollBarsEnabled = false };
browser.ScriptErrorsSuppressed = true;
initheight = 0;
browser.Navigate(m_Url);
browser.DocumentCompleted += WebBrowser_DocumentCompleted;
while (browser.ReadyState != WebBrowserReadyState.Complete)
{
Application.DoEvents();
}
browser.Dispose();
}
private void WebBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
// Capture
var browser = (WebBrowser)sender;
browser.ClientSize = new Size(browser.Document.Body.ScrollRectangle.Width, browser.Document.Body.ScrollRectangle.Bottom);
browser.ScrollBarsEnabled = false;
m_Bitmap = new Bitmap(browser.Document.Body.ScrollRectangle.Width, browser.Document.Body.ScrollRectangle.Bottom);
browser.BringToFront();
browser.DrawToBitmap(m_Bitmap, browser.Bounds);
// Save as file?
if (m_FileName.Length > 0)
{
// Save
m_Bitmap.SaveJPG100(m_FileName);
}
if (initheight == browser.Document.Body.ScrollRectangle.Bottom)
{
browser.DocumentCompleted -= new WebBrowserDocumentCompletedEventHandler(WebBrowser_DocumentCompleted);
}
initheight = browser.Document.Body.ScrollRectangle.Bottom;
}
}生成压缩包
对于批量生成的图片文件，我们可以生成压缩包为客户提供下载功能，压缩功能引用的是ICSharpCode.SharpZipLib.dll，创建 ZipCompress 类的实例，ZipDirectory(zippath, zipfile, password) 方法，需要提供的参数包括，压缩的目录、生成的压缩文件名，压缩包的打开密码。
示例代码如下：
string zippath = Request.PhysicalApplicationPath + "\\des\\" ;
if (!Directory.Exists(zippath))
{
Directory.CreateDirectory(zippath);
}
string zipfile = Request.PhysicalApplicationPath + "\\des\\test.zip";
ZipCompress allgzip = new ZipCompress();
System.IO.DirectoryInfo alldi = new System.IO.DirectoryInfo(zippath);
string password = "123456";
allgzip.ZipDirectory(zippath, zipfile, password);
//以下是生成完压缩包后，清除目录及文件
string[] allfs = Directory.GetFiles(zippath);
for (int i = 0; i < allfs.Length; i++)
{
File.Delete(allfs[i]);
}
Directory.Delete(zippath);
类及实现代码如下：
public class ZipCompress
{
public byte[] Compress(byte[] inputBytes)
{
using (MemoryStream outStream = new MemoryStream())
{
using (GZipStream zipStream = new GZipStream(outStream, CompressionMode.Compress, true))
{
zipStream.Write(inputBytes, 0, inputBytes.Length);
zipStream.Close(); //很重要，必须关闭，否则无法正确解压
return outStream.ToArray();
}
}
}
public byte[] Decompress(byte[] inputBytes)
{
using (MemoryStream inputStream = new MemoryStream(inputBytes))
{
using (MemoryStream outStream = new MemoryStream())
{
using (GZipStream zipStream = new GZipStream(inputStream, CompressionMode.Decompress))
{
zipStream.CopyTo(outStream);
zipStream.Close();
return outStream.ToArray();
}
}
}
}
public string Compress(string input)
{
byte[] inputBytes = Encoding.Default.GetBytes(input);
byte[] result = Compress(inputBytes);
return Convert.ToBase64String(result);
}
public string Decompress(string input)
{
byte[] inputBytes = Convert.FromBase64String(input);
byte[] depressBytes = Decompress(inputBytes);
return Encoding.Default.GetString(depressBytes);
}
public void Compress(DirectoryInfo dir)
{
foreach (FileInfo fileToCompress in dir.GetFiles())
{
Compress(fileToCompress);
}
}
public void Decompress(DirectoryInfo dir)
{
foreach (FileInfo fileToCompress in dir.GetFiles())
{
Decompress(fileToCompress);
}
}
public void Compress(FileInfo fileToCompress)
{
using (FileStream originalFileStream = fileToCompress.OpenRead())
{
if ((File.GetAttributes(fileToCompress.FullName) & FileAttributes.Hidden) != FileAttributes.Hidden & fileToCompress.Extension != ".gz")
{
using (FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".gz"))
{
using (GZipStream compressionStream = new GZipStream(compressedFileStream, CompressionMode.Compress))
{
originalFileStream.CopyTo(compressionStream);
}
}
}
}
}
public void Decompress(FileInfo fileToDecompress,string desfilename="")
{
using (FileStream originalFileStream = fileToDecompress.OpenRead())
{
string currentFileName = fileToDecompress.FullName;
string newFileName = currentFileName.Remove(currentFileName.Length - fileToDecompress.Extension.Length);
if (desfilename != "")
{
newFileName = desfilename;
}
using (FileStream decompressedFileStream = File.Create(newFileName))
{
using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
{
decompressionStream.CopyTo(decompressedFileStream);
}
}
}
}
public void ZipDirectory(string folderToZip, string zipedFileName,string password)
{
ZipDirectory(folderToZip, zipedFileName,(password==""?string.Empty:password), true, string.Empty, string.Empty, true);
}
public void ZipDirectory(string folderToZip, string zipedFileName, string password, bool isRecurse, string fileRegexFilter, string directoryRegexFilter, bool isCreateEmptyDirectories)
{
FastZip fastZip = new FastZip();
fastZip.CreateEmptyDirectories = isCreateEmptyDirectories;
fastZip.Password = password;
fastZip.CreateZip(zipedFileName, folderToZip, isRecurse, fileRegexFilter, directoryRegexFilter);
}
public void UnZipDirectory(string zipedFileName, string targetDirectory, string password,string fileFilter=null)
{
FastZip fastZip = new FastZip();
fastZip.Password = password;
fastZip.ExtractZip(zipedFileName, targetDirectory,fileFilter);
}
public void UnZip(string zipFilePath, string unZipDir)
{
if (zipFilePath == string.Empty)
{
throw new Exception("压缩文件不能为空！");
}
if (!File.Exists(zipFilePath))
{
throw new FileNotFoundException("压缩文件不存在！");
}
//解压文件夹为空时默认与压缩文件同一级目录下，跟压缩文件同名的文件夹
if (unZipDir == string.Empty)
unZipDir = zipFilePath.Replace(Path.GetFileName(zipFilePath), Path.GetFileNameWithoutExtension(zipFilePath));
if (!unZipDir.EndsWith("/"))
unZipDir += "/";
if (!Directory.Exists(unZipDir))
Directory.CreateDirectory(unZipDir);
using (var s = new ZipInputStream(File.OpenRead(zipFilePath)))
{
ZipEntry theEntry;
while ((theEntry = s.GetNextEntry()) != null)
{
string directoryName = Path.GetDirectoryName(theEntry.Name);
string fileName = Path.GetFileName(theEntry.Name);
if (!string.IsNullOrEmpty(directoryName))
{
Directory.CreateDirectory(unZipDir + directoryName);
}
if (directoryName != null && !directoryName.EndsWith("/"))
{
}
if (fileName != String.Empty)
{
using (FileStream streamWriter = File.Create(unZipDir + theEntry.Name))
{
int size;
byte[] data = new byte[2048];
while (true)
{
size = s.Read(data, 0, data.Length);
if (size > 0)
{
streamWriter.Write(data, 0, size);
}
else
{
break;
}
}
}
}
}
}
}
}小结
对于生成的图片文件，我们还可以结合其它的API应用，来判断图片是否有被PS的情况，来提升和扩展应用程序的功能。另外，对于被访问的动态页面，建议使用访问控制，只有正常登录或提供访问令牌的用户才可以生成结果图片，以保证数据的安全性。
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