Class wwHTTP
This class can be used to make HTTP requests to Web servers, to retrieve data. You can also send data to the server using POST or PUT operations. All HTTP verbs are supported.
At it's simplest you can retrieve HTTP content like this:
foxpro
foxpro
loHttp = CREATEOBJECT("wwHttp")
lcHtml = loHttp.Get("https://markdownmonster.west-wind.com")
Content retrieved can also be saved to a file directly using the lcOutputName parameter of all the retrieval routines (.Get(), .Post(), .Put(), .Delete()):
foxpro
foxpro
loHttp = CREATEOBJECT('wwhttp')
loHttp.Get("https://west-wind.com/files/wwclient.zip","c:\temp\wwclient.zip")
You can also POST data to the server using the .AddPostKey() method which lets you post either individual form values or a complete POST buffer to the server.
POST some data to a server using HTML style form vars:
foxpro
foxpro
oHTTP=CREATEOBJECT("wwHTTP")
oHTTP.AddPostKey("FirstName","Rick")
oHTTP.AddPostKey("LastName","Strahl")
oHTTP.AddPostKey("Company","West Wind Technologies")
*** Optionally add custom headers
oHTTP.AppendHeader("cache-control","private")
oHttp.AppendHeader("Custom-Header","Custom value")
lcHTML = oHTTP.Post("http://www.west-wind.com/wconnect/TestPage.wwd")
ShowHTML( lcHTML )
alternately you can post an entire buffer of data to the server. This is common when you sent JSON or XML documents:
foxpro
foxpro
loHttp = CREATEOBJECT("wwHttp")
*** Specify that we want to post raw data and a custom content type
loHttp.cContentType = "application/json" && Content type of the data posted
* loHttp.cHttpVerb = "POST" && Use for anything but POST/GET verbs (PUT/DELETE/HEAD/OPTIONS)
*** Load up the XML data any way you need
lcJson = FILETOSTR("Data.json")
*** New simpler syntax for raw buffers
lcJsonResult = loHttp.Post("http://www.west-wind.com/JsonService.xsvc", lcJson)
*** Alternately you can also explicitly use `.AddPostKey()` (same behavior)
loHttp.AddPostKey(lcJson)
lcJsonResult = loHttp.Post("http://www.west-wind.com/JsonService.xsvc")
* do something with the JSON data
The wwHttp class provides HTTP access via WinInet to Visual FoxPro application. This class provides tight control over most aspects of the HTTP protocol including HTTP headers (client and server side), timeouts, proxy support, authentication, SSL connectivity as well as providing support for asynchronous HTTP operation.
For a variety of examples of using this class please see:
Based on: Relation
Stored in: wwHTTP.prg
Remarks
External Dependencies
wwIPstuff.dll
zLib.dll
Class Members
| Member | Description | |
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OnHttpBufferUpdate | The OnHttpBufferUpdate() method is called whenever a buffer is downloaded from the server and allows you to display download status information for large file downloads. It's also useful for freeing… |
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OnHttpPostConnect | This event fires after the Http connection has been established and can be useful to set specific WinInet options on the HTTP connection. Use this event to call `SetOption()` to apply HTTP connect… |
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AddPostKey | Set POST data to send on a POST or PUT request. This method sets the post buffer and supports encoding for HTML form based uploads as well as raw data buffers. Several different POST mechanisms…
o.AddPostKey(tcKey, tcValue)
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AddPostFile | A specific version of `AddPostKey()` designed for File or Data uploads for multi-part HTTP forms. > This method requires that `nHttpPostMode=2`. If not set an error occurs. This method provides…
o.AddPostFile(tcKey, tcValue,
tlIsFile, tcContentType,
tcExtraHeaders)
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Get | Uses an HTTP `GET` operation to retrieve Web content from a URL. `GET` operations pass only the URL and no content body data and expect back an HTTP response. ```foxpro DO wwHttp LOCAL loHttp as…
o.Get(lcUrl, lcUserName, lcPassword, lcOutputFile)
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Post | Uses an HTTP `POST` operation to post content to the Web server and to retrieve Web content from a URL. You can pass in a URL and the raw Post data to send. Make sure to set `.cContentType` if using…
o.Post(lcUrl, lcPostData, lcOutputFile)
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Put | Uses an HTTP `PUT` operation to post content to the server and to retrieve Web content from a URL. ```foxpro DO wwHttp LOCAL loHttp as wwHttp OF wwhttp.prg loHttp = CREATEOBJECT("wwHttp") *** post…
o.Put(lcUrl, lcUserName, lcPassword, lcOutputFile)
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Delete | Uses an HTTP `DELETE` operation to retrieve Web content from a URL. ```foxpro DO wwHttp LOCAL loHttp as wwHttp OF wwhttp.prg loHttp = CREATEOBJECT("wwHttp") lcJsonResponse =…
o.Delete(lcUrl, lcUserName, lcPassword, lcOutputFile)
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Send | This is the generic (and classical) Http operation that handles all types of HTTP requests. The `.Get()`,`.Post()`,`.Put()`,`.Delete()` methods are simply shortcut wrappers around this method that…
o.Send(lcUrl, lcUsername, lcPassword, lcOutputFile)
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AddHeader | Allows you to add HTTP headers to the HTTP request sent to the server. Headers can be of the standard HTTP header kind like Content-encoding or Cache, or custom headers specific to your application.
o.AddHeader(lcHeader,lcValue)
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AddBasicAuthenticationHeader | Adds a Basic Authentication `Authorize` header with properly encoded scheme and encoded username and password to the Http headers of the request. > Immediately sends this username and password with…
o.AddBasicAuthenticationHeader(lcUsername, lcPassword)
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GetHttpHeader | Retrieves an HTTP once the Response has been returned. Requires that a successfull call to HttpGet or HttpGetEx was made that returns a header in cHttpHeaders.
o.wwHTTP.GetHttpHeader(lcHeader)
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HttpCancelDownload | Cancels a download if OnHttpBufferUpdate are hooked up to do incremental URL downloads. When called cancels the current download.
o.httpcanceldownload()
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HttpClose | Closes an HTTP Session opened with HTTPConnect(). This method is automatically called during DESTROY.
o.httpclose()
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HttpConnect | This low level HTTP method initiates a low level HTTP request for use with HTTPGetEx by establishing an IP Session and connecting to a target server. The main purpose of this method is to specify the…
o.httpconnect(lcServer, lcUsername, lcPassword, llHTTPS)
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HttpGetEx | This low level method is the full featured HTTP access method that provides full support for the HTTP protocol including POST data, Basic Authentication and HTTPS protocol support. Requires…
o.HTTPGetEx(tcPage, @tcBuffer, @tnBufferSize, tcHeaders, tcFileName)
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HttpGetHeader | Retrieves just the HTTP header from a URL. Useful for retrieving information about a request prior to actually downloading the full URL. You can spy the content length from the header for…
o.httpgetheader(tcPage, tcHeaders, tnHeaderSize)
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HttpPing | Use this method to *ping* a Web site to check whether a valid Internet connection can be made. You provide a fully qualified URL - preferably a static page that loads fast - to check, and you can…
o.HTTPPing(lnTimeout,lcUrl)
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InternetCrackUrl | This method breaks down an incoming URL into its component pieces.
loUrl = o.InternetCrackUrl(lcUrl)
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WinInetSetTimeout | Allows setting the timeout period for an HTTP request. The timeout is specified in seconds and controls how long a Connect, Read or Send operation waits before being considered timed out. Call…
o.wininetsettimeout(dwTimeoutSecs)
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GetSystemErrorMsg | Returns a WinInet or Win32 API error message.
o.getsystemerrormsg(lnErrorNo, llAPI)
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GetMessageFromResultCode | Returns the HTTP message for a given HTTP Result Code. For example returns Not Authorized for a 401 result code, or Not Authorized for a 404. The most HTTP errors are mapped and returned in this…
o.GetMessageFromResultCode(lcResultCode)
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SetOption | Sets an Internet option on a given connection handle. The handle can be either an Internet handle or the Http handle so this method has to be called after the connection has been opened. It is meant…
o.SetOption(lnHandle,lnOptionId,lnOptionValue)
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GetCertificates | Retrieves a list of certificates that are installed on the local machine as a collection. The collection contains a set of objects that hold the raw certificate information as a .NET object as…
o.GetCertificates(lcStoreName, lcLocation)
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cErrorMsg | Last Error Message Text for the last operation. Implemented only for SMTP and HTTP operations. |
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cContentType | Sets the Content Type for **POST** data sent to the server. Use the content type if you're posting raw POST buffers for data like JSON (`application/json`) or XML (`text/xml`) or raw binary data. >… |
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cExtraHeaders | Allows you to specify extra HTTP or SMTP headers when sending requests to Web Servers or SMTP serveres. Any extra headers provided should be in the following key:value format: **Content-type:… |
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chttpheaders | This property is set when calling HTTPGetEx and contains the entire HTTP header of a request. This property is a result property only after an HTTP request completes. Use cExtraHeaders to specify… |
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cHttpVerb | Allows you to override the HTTP Verb for the request. Use this option if you need to set an HTTP verb other than GET or POST. The default is blank which means GET or POST is auto-selected based on… |
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cHTTPProxyByPass | This property allows you to specify a list of host names or IP Addresses that should not be routed through the proxy server. IOW, this list allows you to directly access the requested domains/IPs… |
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cHTTPProxyName | Use this method to override proxy information if the default Proxy connection types via [nHTTPConnectType](vfps://Topic/wwHTTP%3A%3Anhttpconnecttype) don't work for you. You can specify the… |
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cHttpProxyUserName | Proxy server user name if the proxy requires a login. |
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cHttpProxyPassword | Proxy server password if the proxy requires a login. |
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cLink | HTTP Link to visit on a site. Site relative URL. Example: /default.asp, /, /wconnect.dll?wwDemo~TestPage |
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cResultCode | Returns the HTTP result code from a request. These are HTTP spec result codes that are typically returned in the HTTP response header from the Web Server. A valid response from a server is "200" or… |
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cResultCodeMessage | Returns the HTTP Result Code message based on the active [cResultCode](vfps://Topic/_0XY0UL6DP) property. For example returns "Not Authorized" for a 401 result code, "Not Found" for a 404, "Server… |
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cpassword | Password to log on to server (applies to FTP and HTTP) |
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cserver | HTTP Server Address. Format: www.west-wind.com, or 111.111.111.111 |
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cUserAgent | The name of the user agent that the wwIPStuff client sends to the Web server. Change this property if you need to emulate a specific browser like Internet Explorer or Netscape. |
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cusername | Username that can be used for HTTP authentication that requires username and password. Authentication Schemes supported are: * Windows/NTLM/Negotiate Authentication * Basic Authentication * Digest… |
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nServiceFlags | Use this property to override internet service connection flags used by WinINet. Used in the call to InternetConnect(). |
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nconnecttimeout | Allows setting the timeout period for an HTTP request. The timeout is specified in seconds and controls how long a Connect, Read or Send operation waits before being considered timed out. Should be… |
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nerror | Returns the error code from the last request. This value is 0 if no error occurred or non-zero if an error occurred. This property should be used to definitively determine whether a request… |
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lCacheRequest | If set causes the current request to be cached if possible so that subsequent requests do not go back to the server to retrieve the data. By default requests are forced to be refreshed on every hit… |
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lAllowGZip | Determines whether wwHTTP requests and decodes GZip content. If set wwHttp sends the gzip Accept-Encoding header. If the server is capable of gzip it will return GZIP data to the client and wwHTTP… |
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lDecodeUtf8 | If .T. (default) automatically decodes UTF-8 encoded content from the server. Looks for the `charset=utf-8` in the `Content-Type`. |
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lHttpCancelDownload | Property that can be read to see whether the current request was cancelled with [HTTPCancelDownload](vfps://Topic/wwHTTP%3A%3AHTTPCanceldownload). This method is useful when checking the completion… |
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lIgnoreCertificateWarnings | When .T. ignores warnings about invalid certificates. If the server responds with warnings rather than a complete revoked and out of date certificate, these warnings are ignored and the request… |
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lUseLargePostBuffer | Flag that can be set to cause the Post Buffer to use a File Stream to hold POST data. This allows the buffer to be larger than 16 megs to send large content to the server. ```foxpro DO wwHttp loHttp… |
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nClientCertificateIndex | |
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nHttpConnectType | Allows to specify how the connection is opened. 1 - Direct*, 0 - PreConfig (trying to use IE connection and Proxy settings) 3 - Proxy ( manually connecting through a Proxy) 4 - PreConfig (using IE… |
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nHttpServiceFlags | Flags that are used on the HTTP connection in WinInet. This method is needed to pass options that require setting values. For option switches you can use the `.nHttpServiceFlags` or `.nServiceFlags`… |
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nHttpPostMode | Sets the form POST mode for requests specifically for **key value pair** form submissions that use `AddPostKey(lcKey, lcValue)`. This property only applies to **Url Encoded**… |
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nhttpworkbuffersize | Size of the download HTTP buffer used while downloading dynamically sized requests with HTTPGetEx. This is the size of chunks that will be pulled at a time and also determines how often… |
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oPostStream | Internal `wwFileStream` instance that holds large string data when `.lUseLargePostBuffer` is used. |
See also
West Wind Web Connection
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