OpenTop C++ class: HttpURLConnection

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Cross-Platform C++

SUMMARY: CONSTRUCTOR | METHOD

DETAIL: CONSTRUCTOR | METHOD

ot::net
class HttpURLConnection (abstract)

#include "ot/net/HttpURLConnection.h"

A specialized URLConnection class that represents a connection with a resource specified by a HTTP URL.

HTTP stands for Hyper Text Transfer Protocol, which is defined by RFCs published by the Internet Engineering Task Force.

A HttpURLConnection instance can make only one HTTP request (although this one request may involve several message exchanges if HTTP redirection or authorization is involved). When an application makes multiple HTTP requests to the same server, the underlying OpenTop framework classes will attempt to maximize network efficiency by making use of persistent HTTP connections. Note, however, that not all HTTP servers support persistent connections and only idempotent requests will be considered for transmission over an existing persistent connection..

Managing persistent connections

TCP/IP connections employed by HttpURLConnection are created and managed by the global instance of the web::HttpClientConnectionManager class. Changes to the properties of this global object will affect all users of HttpURLConnection..

Communicating via a proxy server

If the system property http.proxySet is set to true, default values for the HTTP proxy server and port are read from the http.proxyHost and http.proxyPort system properties respectively.

See also:: System::SetProperty()

Constructor/Destructor Summary
`HttpURLConnection(const URL& url)` Constructs a HttpURLConnection for the specified HTTP URL.

Method Summary
`static bool`	`GetDefaultFollowRedirects()` Returns the global `FollowRedirects` value which is used to initialize new HttpURLConnection objects.
`virtual RefPtr< InputStream >`	`getErrorStream() const=0` Returns an InputStream that contains the output from the HTTP server after an error occurs.
`virtual bool`	`getFollowRedirects() const=0` Returns a flag indicating whether HTTP redirects will be followed.
`virtual String`	`getRequestMethod() const=0` Returns the request method.
`virtual int`	`getResponseCode()=0` Returns the numeric response code returned from the HTTP server.
`virtual String`	`getResponseMessage()=0` Returns the message text from the HTTP response line.
`static void`	`SetDefaultFollowRedirects(bool bFollow)` Set the global `FollowRedirects` value which is used to initialize new HttpURLConnection objects.
`virtual void`	`setFollowRedirects(bool bFollow)=0` Specifies whether or not HTTP redirect responses should be followed.
`virtual void`	`setRequestMethod(const String& method)=0` Sets the request method that will be transmitted to the HTTP server.

Methods inherited from class ot::ManagedObject

addRef(), getRefCount(), onFinalRelease(), operator=(const ManagedObject&), release()

Methods inherited from class ot::net::URLConnection

connect(), getConnectTimeout(), getContentEncoding(), getContentLength(), getContentType(), getDate(), GetDefaultConnectTimeout(), GetDefaultTimeout(), GetDefaultUseCaches(), getDoInput(), getDoOutput(), getHeaderField(const String&), getHeaderField(size_t), getHeaderFieldCount(), getHeaderFieldDate(const String&), getHeaderFieldKey(size_t), getHeaderFieldLong(const String&, long), getInputStream(), getLastModified(), getOutputStream(), getRequestProperty(const String&), getTimeout(), getURL(), getUseCaches(), isConnected(), resetHeaderFields(), setConnected(bool), setConnectTimeout(size_t), SetDefaultConnectTimeout(size_t), SetDefaultTimeout(size_t), SetDefaultUseCaches(bool), setDoInput(bool), setDoOutput(bool), setRequestProperty(const String&, const String&), setTimeout(size_t), setURL(const URL&), setUseCaches(bool)

Enumerations

`enum HttpResponseCode {`	`HTTP_ACCEPTED =202,`
	`HTTP_BAD_GATEWAY =502,`
	`HTTP_BAD_METHOD =405,`
	`HTTP_BAD_REQUEST =400,`
	`HTTP_CLIENT_TIMEOUT =408,`
	`HTTP_CONFLICT =409,`
	`HTTP_CREATED =201,`
	`HTTP_ENTITY_TOO_LARGE =413,`
	`HTTP_FORBIDDEN =403,`
	`HTTP_GATEWAY_TIMEOUT =504,`
	`HTTP_GONE =410,`
	`HTTP_INTERNAL_ERROR =500,`
	`HTTP_LENGTH_REQUIRED =411,`
	`HTTP_MOVED_PERM =301,`
	`HTTP_MOVED_TEMP =302,`
	`HTTP_MULT_CHOICE =300,`
	`HTTP_NO_CONTENT =204,`
	`HTTP_NOT_ACCEPTABLE =406,`
	`HTTP_NOT_AUTHORITATIVE =203,`
	`HTTP_NOT_FOUND =404,`
	`HTTP_NOT_IMPLEMENTED =501,`
	`HTTP_NOT_MODIFIED =304,`
	`HTTP_OK =200,`
	`HTTP_PARTIAL =206,`
	`HTTP_PAYMENT_REQUIRED =402,`
	`HTTP_PRECON_FAILED =412,`
	`HTTP_PROXY_AUTH =407,`
	`HTTP_REQ_TOO_LONG =414,`
	`HTTP_RESET =205,`
	`HTTP_SEE_OTHER =303,`
	`HTTP_UNAUTHORIZED =401,`
	`HTTP_UNAVAILABLE =503,`
	`HTTP_UNSUPPORTED_TYPE =415,`
	`HTTP_USE_PROXY =305,`
	`HTTP_VERSION =505}`

Constructor/Destructor Detail

HttpURLConnection

 HttpURLConnection(const URL& url)

Constructs a HttpURLConnection for the specified HTTP URL.

Method Detail

GetDefaultFollowRedirects

static bool GetDefaultFollowRedirects()

Returns the global FollowRedirects value which is used to initialize new HttpURLConnection objects. If this has not been explicitly set, the default value is true.

See also:: SetDefaultFollowRedirects()

getErrorStream

virtual RefPtr< InputStream > getErrorStream() const=0

Returns an InputStream that contains the output from the HTTP server after an error occurs. For example, if a request results in a "404 File Not Found" error, the server may respond with additional useful information. This additional data (if any) will be returned in the error stream.

Returns:: an InputStream or null if no error occurred, or this HttpURLConnection is not yet connected to the HTTP server.

getFollowRedirects

virtual bool getFollowRedirects() const=0

Returns a flag indicating whether HTTP redirects will be followed.

See also:: setFollowRedirects() , SetDefaultFollowRedirects()

getRequestMethod

virtual String getRequestMethod() const=0

Returns the request method.

See also:: setRequestMethod()

getResponseCode

virtual int getResponseCode()=0

Returns the numeric response code returned from the HTTP server. This will attempt to connect to the HTTP server and access the specified resource if it is not already connected.

Refer to the enumeration HttpURLConnection::HttpResponseCode for a list of possible values.

Exceptions:: IOException - is an error occurs while reading from or writing to the HTTP server.

See also:: getResponseMessage()

getResponseMessage

virtual String getResponseMessage()=0

Returns the message text from the HTTP response line. For example, an HTTP response of HTTP/1.1 200 OK will return "OK".

See also:: getResponseCode()

SetDefaultFollowRedirects

static void SetDefaultFollowRedirects(bool bFollow)

Set the global FollowRedirects value which is used to initialize new HttpURLConnection objects. Setting this does not affect any HttpURLConnection objects already constructed.

The default value is true.

See also:: setFollowRedirects() , GetDefaultFollowRedirects()

setFollowRedirects

virtual void setFollowRedirects(bool bFollow)=0

Specifies whether or not HTTP redirect responses should be followed. The HTTP protocol allows for resources to be moved from one location to another. When this occurs, the original server may respond to the client with a HTTP_MOVED_PERM (301) or HTTP_MOVED_TEMP (302) message. When redirects are enabled, this will cause the resource to be fetched from the new location, otherwise the request will fail with a FileNotFoundException.

See also:: getFollowRedirects()

setRequestMethod

virtual void setRequestMethod(const String& method)=0

Sets the request method that will be transmitted to the HTTP server. The default is GET for input requests and POST for output requests. Other possible alternatives are:-