-
Implements a simple HTTP (Web) client in an COMponent.
[
SimpleWebClient |
Source |
Keywords |
Summary | Ancestors | All Members | Descendants ]
- DESCRIPTION
- USAGE
- EXAMPLE
- ADMINISTRATIVE
- SEE ALSO
Class Summary
class ATL_NO_VTABLE CSimpleHTTPClient :
public CComObjectRootEx<CComMultiThreadModel>,
public CComCoClass<CSimpleHTTPClient, &CLSID_SimpleHTTPClient>,
public ISupportErrorInfo,
public IDispatchImpl<ISimpleHTTPClient, &IID_ISimpleHTTPClient, &LIBID_SIMPLEWEBCLIENTLib>
{
public:
- CSimpleHTTPClient() ;
- STDMETHOD(DownloadPage)( BSTR BPageURL, VARIANT *pvPageContent, VARIANT *pvPageType, long lRequestedType);
- STDMETHOD(get_Timeout)( long *pVal);
- STDMETHOD(put_Timeout)( long newVal);
protected:
}; // CSimpleHTTPClient
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DESCRIPTION
This component implement a very basic HTTP client:
 | Provides one single method: Download (send an HTTP GET request and retrieve the document)
| Provides a timeout feature
| Handles WIN32 errors and provides COM error reporting (ISupportErrorInfo/IErrorInfo)
| Supports text data (uses BSTR) and binary data (uses SAFEARRAY of BYTEs)
| | | |
This component was designed for performance; it retrieves the document
in memory, it's very small (32Ko) and uses the WIN32 WinInet API
(low-level API for HTTP).
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USAGE
To use this COMponent:
| Create an instance of this class
| Optionally, set the timeout property (in milliseconds)
| Call method DownloadPage
| Delete instance of the class
| | | |
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EXAMPLE
<%
Dim oHTTP
Set oHTTP = Server.CreateObject("Emmanuel.SimpleHTTPClient.1")
Dim page_url
page_url = Request.Form("PAGE_URL")
Dim page_content
Dim page_type
On Error Resume Next
oHTTP.DownloadPage page_url, page_content, page_type
If Err <> 0 Then
%>
<HTML>
<HEAD>
<TITLE>Error When Downloading Page <%=page_url%></TITLE>
</HEAD>
<BODY>
<P><H2>Error When Downloading Page <%=page_url%></H2></P>
<P><B><%=Err.Description%></B></P>
</BODY>
</HTML>
<%
Else
' No error: send back the page
Response.Clear
Response.ContentType = page_type
Response.BinaryWrite page_content
End If
%>
</PRE>
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ADMINISTRATIVE
Author Emmanuel KARTMANN - Emmanuel KARTMANN
Date Friday 2/4/00 2:48:59 PM
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SEE ALSO
WinInet
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CSimpleHTTPClient() ;
Purpose: create an instance of the class
Parameters: none (C++ constructor)
Return value : none (C++ constructor)
Description :
CSimpleHTTPClient()
;
Function is currently defined inline.
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STDMETHOD(DownloadPage)( BSTR BPageURL, VARIANT *pvPageContent, VARIANT *pvPageType, long lRequestedType);
Purpose: download a document via HTTP
Parameters:
- in BPageURL
- Uniform Resource Locator of the document (its location)
- out pvPageContent
- content of the document. This variant's sub-type
is the one requested (lRequestedType).
- out pvPageType
- type of document (the HTTP Content-Type, e.g.
"text/html", "image/gif", etc...)
- in lRequestedType
- type of variable to create/store in pvPageContent.
Can be any of the following values:
| 0 (icString): the document is returned in a
variable of type Variant/String (this is the
default)
| 1 (icVariant): the document is returned in a
variable of type Variant/SafeArray of BYTEs
| |
Return value : HRESULT = S_OK for success, otherwise
an error occurred.
Description : CAUTION: if the document type is incompatible
with the requested type, the page content may
contain corrupted values (i.e. if you download an
an image and try to store it into a string,
you won't get anything useful).
STDMETHOD(DownloadPage)(/*[in]*/ BSTR BPageURL, /*[out]*/ VARIANT *pvPageContent, /*[out]*/ VARIANT *pvPageType, /*[in, optional, default(0)]*/long lRequestedType);
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STDMETHOD(get_Timeout)( long *pVal);
Purpose: return the timeout value (in milliseconds)
Parameters:
- out pVal
- current timeout value
Return value : HRESULT = S_OK for success, otherwise
an error occurred.
Description : -
STDMETHOD(get_Timeout)(/*[out, retval]*/ long *pVal);
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STDMETHOD(put_Timeout)( long newVal);
Purpose: set the timeout value (in milliseconds)
Parameters:
- in newVal
- new timeout value
Return value : HRESULT = S_OK for success, otherwise
an error occurred.
Description : -
STDMETHOD(put_Timeout)(/*[in]*/ long newVal);
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All Members
- public:
- STDMETHOD(DownloadPage)( BSTR BPageURL, VARIANT *pvPageContent, VARIANT *pvPageType, long lRequestedType);
- STDMETHOD(get_Timeout)( long *pVal);
- STDMETHOD(put_Timeout)( long newVal);
- protected:
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Ancestors
Inheritance chain for CSimpleHTTPClient:
| CComCoClass
| CComObjectRootEx
| IDispatchImpl
| ISupportErrorInfo
| | | |
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Descendants
Class is not inherited by any others.
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CSimpleHTTPClient