高級網頁抓取功能
HttpIdentity 功能
一些網站系統要求使用者登入後才能查看內容; 在這種情況下,我們可以使用 HttpIdentity: -
HttpIdentity id = new HttpIdentity();
id.NetworkUsername = "username";
id.NetworkPassword = "pwd";
Identities.Add(id);
HttpIdentity id = new HttpIdentity();
id.NetworkUsername = "username";
id.NetworkPassword = "pwd";
Identities.Add(id);
Dim id As New HttpIdentity()
id.NetworkUsername = "username"
id.NetworkPassword = "pwd"
Identities.Add(id)
IronWebScraper最令人印象深刻且強大的功能之一是能夠使用成千上萬的唯一(用戶憑據和/或瀏覽器引擎)來偽裝或抓取網站,使用多重登入會話。
public override void Init()
{
License.LicenseKey = " LicenseKey ";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
var proxies = "IP-Proxy1: 8080,IP-Proxy2: 8081".Split(',');
foreach (var UA in IronWebScraper.CommonUserAgents.ChromeDesktopUserAgents)
{
foreach (var proxy in proxies)
{
Identities.Add(new HttpIdentity()
{
UserAgent = UA,
UseCookies = true,
Proxy = proxy
});
}
}
this.Request("http://www.Website.com", Parse);
}
public override void Init()
{
License.LicenseKey = " LicenseKey ";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
var proxies = "IP-Proxy1: 8080,IP-Proxy2: 8081".Split(',');
foreach (var UA in IronWebScraper.CommonUserAgents.ChromeDesktopUserAgents)
{
foreach (var proxy in proxies)
{
Identities.Add(new HttpIdentity()
{
UserAgent = UA,
UseCookies = true,
Proxy = proxy
});
}
}
this.Request("http://www.Website.com", Parse);
}
Public Overrides Sub Init()
License.LicenseKey = " LicenseKey "
Me.LoggingLevel = WebScraper.LogLevel.All
Me.WorkingDirectory = AppSetting.GetAppRoot() & "\ShoppingSiteSample\Output\"
Dim proxies = "IP-Proxy1: 8080,IP-Proxy2: 8081".Split(","c)
For Each UA In IronWebScraper.CommonUserAgents.ChromeDesktopUserAgents
For Each proxy In proxies
Identities.Add(New HttpIdentity() With {
.UserAgent = UA,
.UseCookies = True,
.Proxy = proxy
})
Next proxy
Next UA
Me.Request("http://www.Website.com", Parse)
End Sub
您有多個屬性可以提供不同的行為,因此可以防止網站封鎖您。
以下是其中一些屬性: -
- NetworkDomain : 用於使用者驗證的網域。 支持Windows、NTLM、Kerberos、Linux、BSD和Mac OS X網絡。 必須與 (NetworkUsername 和 NetworkPassword) 一起使用
- NetworkUsername:用於用戶驗證的網絡/HTTP 用戶名。 支持 Http、Windows 網路、NTLM、Kerberos、Linux 網路、BSD 網路和 Mac OS。
- NetworkPassword:用於用戶身份驗證的網路/HTTP 密碼。 支持Http、Windows網絡、NTLM、Keroberos、Linux網絡、BSD網絡和Mac OS。
- 代理:設定代理設定
- UserAgent:設定瀏覽器引擎(Chrome 桌面版、Chrome 手機版、Chrome 平板版、IE 和 Firefox 等)。
- HttpRequestHeaders:適用於自定義標頭值,將與此身份一起使用,並接受字典對象(Dictionary <string, string>)
UseCookies:啟用/禁用使用 cookies
IronWebScraper 使用隨機身份運行抓取器。 如果我們需要指定使用特定的身份來解析頁面,我們可以這樣做。
public override void Init()
{
License.LicenseKey = " LicenseKey ";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
HttpIdentity identity = new HttpIdentity();
identity.NetworkUsername = "username";
identity.NetworkPassword = "pwd";
Identities.Add(id);
this.Request("http://www.Website.com", Parse, identity);
}
public override void Init()
{
License.LicenseKey = " LicenseKey ";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
HttpIdentity identity = new HttpIdentity();
identity.NetworkUsername = "username";
identity.NetworkPassword = "pwd";
Identities.Add(id);
this.Request("http://www.Website.com", Parse, identity);
}
Public Overrides Sub Init()
License.LicenseKey = " LicenseKey "
Me.LoggingLevel = WebScraper.LogLevel.All
Me.WorkingDirectory = AppSetting.GetAppRoot() & "\ShoppingSiteSample\Output\"
Dim identity As New HttpIdentity()
identity.NetworkUsername = "username"
identity.NetworkPassword = "pwd"
Identities.Add(id)
Me.Request("http://www.Website.com", Parse, identity)
End Sub
啟用網頁快取功能
此功能用於緩存請求的頁面。 它經常在開發和測試階段使用; 允許開發者在更新代碼後緩存所需的頁面以供重用。 這使您能夠在重新啟動您的網頁抓取工具後在緩存的頁面上執行您的代碼,而不需要每次都連接到實時網站(行動重播)。
您可以在 Init() 方法中使用它
EnableWebCache();
或
EnableWebCache(Timespan Expiry);
它將您的快取資料儲存到工作目錄資料夾下的WebCache資料夾中。
public override void Init()
{
License.LicenseKey = " LicenseKey ";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
EnableWebCache(new TimeSpan(1,30,30));
this.Request("http://www.WebSite.com", Parse);
}
public override void Init()
{
License.LicenseKey = " LicenseKey ";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
EnableWebCache(new TimeSpan(1,30,30));
this.Request("http://www.WebSite.com", Parse);
}
Public Overrides Sub Init()
License.LicenseKey = " LicenseKey "
Me.LoggingLevel = WebScraper.LogLevel.All
Me.WorkingDirectory = AppSetting.GetAppRoot() & "\ShoppingSiteSample\Output\"
EnableWebCache(New TimeSpan(1,30,30))
Me.Request("http://www.WebSite.com", Parse)
End Sub
IronWebScraper 也具備一些功能,能夠讓您的引擎在重啟代碼後繼續抓取,通過使用 Start(CrawlID) 設定引擎的啟動過程名稱來實現。
static void Main(string [] args)
{
// Create Object From Scraper class
EngineScraper scrape = new EngineScraper();
// Start Scraping
scrape.Start("enginestate");
}
static void Main(string [] args)
{
// Create Object From Scraper class
EngineScraper scrape = new EngineScraper();
// Start Scraping
scrape.Start("enginestate");
}
Shared Sub Main(ByVal args() As String)
' Create Object From Scraper class
Dim scrape As New EngineScraper()
' Start Scraping
scrape.Start("enginestate")
End Sub
執行請求和回應將被保存到工作目錄內的 SavedState 資料夾中。
限流
我們可以控制每個域的最小和最大連接數以及連接速度。
public override void Init()
{
License.LicenseKey = "LicenseKey";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
// Gets or sets the total number of allowed open HTTP requests (threads)
this.MaxHttpConnectionLimit = 80;
// Gets or sets minimum polite delay (pause)between request to a given domain or IP address.
this.RateLimitPerHost = TimeSpan.FromMilliseconds(50);
// Gets or sets the allowed number of concurrent HTTP requests (threads) per hostname
// or IP address. This helps protect hosts against too many requests.
this.OpenConnectionLimitPerHost = 25;
this.ObeyRobotsDotTxt = false;
// Makes the WebSraper intelligently throttle requests not only by hostname, but
// also by host servers' IP addresses. This is polite in-case multiple scraped domains
// are hosted on the same machine.
this.ThrottleMode = Throttle.ByDomainHostName;
this.Request("https://www.Website.com", Parse);
}
public override void Init()
{
License.LicenseKey = "LicenseKey";
this.LoggingLevel = WebScraper.LogLevel.All;
this.WorkingDirectory = AppSetting.GetAppRoot() + @"\ShoppingSiteSample\Output\";
// Gets or sets the total number of allowed open HTTP requests (threads)
this.MaxHttpConnectionLimit = 80;
// Gets or sets minimum polite delay (pause)between request to a given domain or IP address.
this.RateLimitPerHost = TimeSpan.FromMilliseconds(50);
// Gets or sets the allowed number of concurrent HTTP requests (threads) per hostname
// or IP address. This helps protect hosts against too many requests.
this.OpenConnectionLimitPerHost = 25;
this.ObeyRobotsDotTxt = false;
// Makes the WebSraper intelligently throttle requests not only by hostname, but
// also by host servers' IP addresses. This is polite in-case multiple scraped domains
// are hosted on the same machine.
this.ThrottleMode = Throttle.ByDomainHostName;
this.Request("https://www.Website.com", Parse);
}
Public Overrides Sub Init()
License.LicenseKey = "LicenseKey"
Me.LoggingLevel = WebScraper.LogLevel.All
Me.WorkingDirectory = AppSetting.GetAppRoot() & "\ShoppingSiteSample\Output\"
' Gets or sets the total number of allowed open HTTP requests (threads)
Me.MaxHttpConnectionLimit = 80
' Gets or sets minimum polite delay (pause)between request to a given domain or IP address.
Me.RateLimitPerHost = TimeSpan.FromMilliseconds(50)
' Gets or sets the allowed number of concurrent HTTP requests (threads) per hostname
' or IP address. This helps protect hosts against too many requests.
Me.OpenConnectionLimitPerHost = 25
Me.ObeyRobotsDotTxt = False
' Makes the WebSraper intelligently throttle requests not only by hostname, but
' also by host servers' IP addresses. This is polite in-case multiple scraped domains
' are hosted on the same machine.
Me.ThrottleMode = Throttle.ByDomainHostName
Me.Request("https://www.Website.com", Parse)
End Sub
節流屬性
MaxHttpConnectionLimit
允許的 HTTP 請求(線程)總數RateLimitPerHost
對指定網域或 IP 位址的請求之間的最小禮貌延遲或暫停(以毫秒為單位)OpenConnectionLimitPerHost
允許的同時 HTTP 請求(執行緒)數量ThrottleMode
使 WebSraper 能夠智能地調節請求速度,不僅依據主機名稱,還根據主機伺服器的 IP 地址。 這是出於禮貌,以防多個抓取的網域託管在同一台機器上。開始使用IronWebscraper
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