URLConnection

URLConnection

protected URLConnection(url: URL!)

Constructs a URL connection to the specified URL. A connection to the object referenced by the URL is not created.

addRequestProperty

open fun addRequestProperty(
    key: String!, 
    value: String!
): Unit

Adds a general request property specified by a key-value pair. This method will not overwrite existing values associated with the same key.

connect

abstract fun connect(): Unit

Opens a communications link to the resource referenced by this URL, if such a connection has not already been established.

If the connect method is called when the connection has already been opened (indicated by the connected field having the value true), the call is ignored.

URLConnection objects go through two phases: first they are created, then they are connected. After being created, and before being connected, various options can be specified (e.g., doInput and UseCaches). After connecting, it is an error to try to set them. Operations that depend on being connected, like getContentLength, will implicitly perform the connection, if necessary.

getAllowUserInteraction

open fun getAllowUserInteraction(): Boolean

Returns the value of the allowUserInteraction field for this object.

getConnectTimeout

open fun getConnectTimeout(): Int

Returns setting for connect timeout.

0 return implies that the option is disabled (i.e., timeout of infinity).

getContent

open fun getContent(): Any!

Retrieves the contents of this URL connection.

This method first determines the content type of the object by calling the getContentType method. If this is the first time that the application has seen that specific content type, a content handler for that content type is created:

1. If the application has set up a content handler factory instance using the setContentHandlerFactory method, the createContentHandler method of that instance is called with the content type as an argument; the result is a content handler for that content type.
2. If no content handler factory has yet been set up, or if the factory's createContentHandler method returns null, then the application loads the class named:

   sun.net.www.content.<<i>contentType</i>>
         

   where <contentType> is formed by taking the content-type string, replacing all slash characters with a period ('.'), and all other non-alphanumeric characters with the underscore character '_'. The alphanumeric characters are specifically the 26 uppercase ASCII letters 'A' through 'Z', the 26 lowercase ASCII letters 'a' through 'z', and the 10 ASCII digits '0' through '9'. If the specified class does not exist, or is not a subclass of ContentHandler, then an UnknownServiceException is thrown.

getContent

open fun getContent(classes: Array<Class<Any!>!>!): Any!

Retrieves the contents of this URL connection.

getContentEncoding

open fun getContentEncoding(): String!

Returns the value of the content-encoding header field.

getContentLength

open fun getContentLength(): Int

Returns the value of the content-length header field.

Note: getContentLengthLong() should be preferred over this method, since it returns a long instead and is therefore more portable.

getContentLengthLong

open fun getContentLengthLong(): Long

Returns the value of the content-length header field as a long.

getContentType

open fun getContentType(): String!

Returns the value of the content-type header field.

getDate

open fun getDate(): Long

Returns the value of the date header field.

getDefaultAllowUserInteraction

open static fun getDefaultAllowUserInteraction(): Boolean

Returns the default value of the allowUserInteraction field.

Ths default is "sticky", being a part of the static state of all URLConnections. This flag applies to the next, and all following URLConnections that are created.

getDefaultRequestProperty

open static fun getDefaultRequestProperty(key: String!): String!

Deprecated: The instance specific getRequestProperty method should be used after an appropriate instance of URLConnection is obtained.

Returns the value of the default request property. Default request properties are set for every connection.

getDefaultUseCaches

open fun getDefaultUseCaches(): Boolean

Returns the default value of a URLConnection's useCaches flag.

Ths default is "sticky", being a part of the static state of all URLConnections. This flag applies to the next, and all following URLConnections that are created.

getDoInput

open fun getDoInput(): Boolean

Returns the value of this URLConnection's doInput flag.

getDoOutput

open fun getDoOutput(): Boolean

Returns the value of this URLConnection's doOutput flag.

getExpiration

open fun getExpiration(): Long

Returns the value of the expires header field.

getFileNameMap

open static fun getFileNameMap(): FileNameMap!

Returns a FileNameMap implementation suitable for guessing a content type based on a URL's "file" component.

getHeaderField

open fun getHeaderField(name: String!): String!

Returns the value of the named header field.

If called on a connection that sets the same header multiple times with possibly different values, only the last value is returned.

getHeaderField

open fun getHeaderField(n: Int): String!

Returns the value for the nth header field. It returns null if there are fewer than n+1fields.

This method can be used in conjunction with the getHeaderFieldKey method to iterate through all the headers in the message.

getHeaderFieldDate

open fun getHeaderFieldDate(
    name: String!, 
    Default: Long
): Long

Returns the value of the named field parsed as date. The result is the number of milliseconds since January 1, 1970 GMT represented by the named field.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

getHeaderFieldInt

open fun getHeaderFieldInt(
    name: String!, 
    Default: Int
): Int

Returns the value of the named field parsed as a number.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

getHeaderFieldKey

open fun getHeaderFieldKey(n: Int): String!

Returns the key for the nth header field. It returns null if there are fewer than n+1 fields.

getHeaderFieldLong

open fun getHeaderFieldLong(
    name: String!, 
    Default: Long
): Long

Returns the value of the named field parsed as a number.

This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.

getHeaderFields

open fun getHeaderFields(): MutableMap<String!, MutableList<String!>!>!

Returns an unmodifiable Map of the header fields. The Map keys are Strings that represent the response-header field names. Each Map value is an unmodifiable List of Strings that represents the corresponding field values.

getIfModifiedSince

open fun getIfModifiedSince(): Long

Returns the value of this object's ifModifiedSince field.

getInputStream

open fun getInputStream(): InputStream!

Returns an input stream that reads from this open connection. A SocketTimeoutException can be thrown when reading from the returned input stream if the read timeout expires before data is available for read.

getLastModified

open fun getLastModified(): Long

Returns the value of the last-modified header field. The result is the number of milliseconds since January 1, 1970 GMT.

getOutputStream

open fun getOutputStream(): OutputStream!

Returns an output stream that writes to this connection.

getPermission

open fun getPermission(): Permission!

Returns a permission object representing the permission necessary to make the connection represented by this object. This method returns null if no permission is required to make the connection. By default, this method returns java.security.AllPermission. Subclasses should override this method and return the permission that best represents the permission required to make a a connection to the URL. For example, a URLConnection representing a file: URL would return a java.io.FilePermission object.

The permission returned may dependent upon the state of the connection. For example, the permission before connecting may be different from that after connecting. For example, an HTTP sever, say foo.com, may redirect the connection to a different host, say bar.com. Before connecting the permission returned by the connection will represent the permission needed to connect to foo.com, while the permission returned after connecting will be to bar.com.

Permissions are generally used for two purposes: to protect caches of objects obtained through URLConnections, and to check the right of a recipient to learn about a particular URL. In the first case, the permission should be obtained after the object has been obtained. For example, in an HTTP connection, this will represent the permission to connect to the host from which the data was ultimately fetched. In the second case, the permission should be obtained and tested before connecting.

getReadTimeout

open fun getReadTimeout(): Int

Returns setting for read timeout. 0 return implies that the option is disabled (i.e., timeout of infinity).

getRequestProperties

open fun getRequestProperties(): MutableMap<String!, MutableList<String!>!>!

Returns an unmodifiable Map of general request properties for this connection. The Map keys are Strings that represent the request-header field names. Each Map value is a unmodifiable List of Strings that represents the corresponding field values.

getRequestProperty

open fun getRequestProperty(key: String!): String!

Returns the value of the named general request property for this connection.

getURL

open fun getURL(): URL!

Returns the value of this URLConnection's URL field.

getUseCaches

open fun getUseCaches(): Boolean

Returns the value of this URLConnection's useCaches field.

guessContentTypeFromName

open static fun guessContentTypeFromName(fname: String!): String!

Tries to determine the content type of an object, based on the specified "file" component of a URL. This is a convenience method that can be used by subclasses that override the getContentType method.

guessContentTypeFromStream

open static fun guessContentTypeFromStream(is: InputStream!): String!

Tries to determine the type of an input stream based on the characters at the beginning of the input stream. This method can be used by subclasses that override the getContentType method.

Ideally, this routine would not be needed. But many http servers return the incorrect content type; in addition, there are many nonstandard extensions. Direct inspection of the bytes to determine the content type is often more accurate than believing the content type claimed by the http server.

setAllowUserInteraction

open fun setAllowUserInteraction(allowuserinteraction: Boolean): Unit

Set the value of the allowUserInteraction field of this URLConnection.

setConnectTimeout

open fun setConnectTimeout(timeout: Int): Unit

Sets a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection. If the timeout expires before the connection can be established, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method may ignore the specified timeout. To see the connect timeout set, please call getConnectTimeout().

Warning: If the hostname resolves to multiple IP addresses, Android's default implementation of HttpURLConnection will try each in RFC 3484 order. If connecting to each of these addresses fails, multiple timeouts will elapse before the connect attempt throws an exception. Host names that support both IPv6 and IPv4 always have at least 2 IP addresses.

setContentHandlerFactory

open static fun setContentHandlerFactory(fac: ContentHandlerFactory!): Unit

Sets the ContentHandlerFactory of an application. It can be called at most once by an application.

The ContentHandlerFactory instance is used to construct a content handler from a content type

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

setDefaultAllowUserInteraction

open static fun setDefaultAllowUserInteraction(defaultallowuserinteraction: Boolean): Unit

Sets the default value of the allowUserInteraction field for all future URLConnection objects to the specified value.

setDefaultRequestProperty

open static fun setDefaultRequestProperty(
    key: String!, 
    value: String!
): Unit

Deprecated: The instance specific setRequestProperty method should be used after an appropriate instance of URLConnection is obtained. Invoking this method will have no effect.

Sets the default value of a general request property. When a URLConnection is created, it is initialized with these properties.

setDefaultUseCaches

open fun setDefaultUseCaches(defaultusecaches: Boolean): Unit

Sets the default value of the useCaches field to the specified value.

setDoInput

open fun setDoInput(doinput: Boolean): Unit

Sets the value of the doInput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoInput flag to true if you intend to use the URL connection for input, false if not. The default is true.

setDoOutput

open fun setDoOutput(dooutput: Boolean): Unit

Sets the value of the doOutput field for this URLConnection to the specified value.

A URL connection can be used for input and/or output. Set the DoOutput flag to true if you intend to use the URL connection for output, false if not. The default is false.

setFileNameMap

open static fun setFileNameMap(map: FileNameMap!): Unit

Sets the FileNameMap.

If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException.

setIfModifiedSince

open fun setIfModifiedSince(ifmodifiedsince: Long): Unit

Sets the value of the ifModifiedSince field of this URLConnection to the specified value.

setReadTimeout

open fun setReadTimeout(timeout: Int): Unit

Sets the read timeout to a specified timeout, in milliseconds. A non-zero value specifies the timeout when reading from Input stream when a connection is established to a resource. If the timeout expires before there is data available for read, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method ignores the specified timeout. To see the read timeout set, please call getReadTimeout().

setRequestProperty

open fun setRequestProperty(
    key: String!, 
    value: String!
): Unit

Sets the general request property. If a property with the key already exists, overwrite its value with the new value.

NOTE: HTTP requires all request properties which can legally have multiple instances with the same key to use a comma-separated list syntax which enables multiple properties to be appended into a single property.

setUseCaches

open fun setUseCaches(usecaches: Boolean): Unit

Sets the value of the useCaches field of this URLConnection to the specified value.

Some protocols do caching of documents. Occasionally, it is important to be able to "tunnel through" and ignore the caches (e.g., the "reload" button in a browser). If the UseCaches flag on a connection is true, the connection is allowed to use whatever caches it can. If false, caches are to be ignored. The default value comes from DefaultUseCaches, which defaults to true.

toString

open fun toString(): String

Returns a String representation of this URL connection.

allowUserInteraction

protected var allowUserInteraction: Boolean

If true, this URL is being examined in a context in which it makes sense to allow user interactions such as popping up an authentication dialog. If false, then no user interaction is allowed.

The value of this field can be set by the setAllowUserInteraction method. Its value is returned by the getAllowUserInteraction method. Its default value is the value of the argument in the last invocation of the setDefaultAllowUserInteraction method.

connected

protected var connected: Boolean

If false, this connection object has not created a communications link to the specified URL. If true, the communications link has been established.

doInput

protected var doInput: Boolean

This variable is set by the setDoInput method. Its value is returned by the getDoInput method.

A URL connection can be used for input and/or output. Setting the doInput flag to true indicates that the application intends to read data from the URL connection.

The default value of this field is true.

doOutput

protected var doOutput: Boolean

This variable is set by the setDoOutput method. Its value is returned by the getDoOutput method.

A URL connection can be used for input and/or output. Setting the doOutput flag to true indicates that the application intends to write data to the URL connection.

The default value of this field is false.

ifModifiedSince

protected var ifModifiedSince: Long

Some protocols support skipping the fetching of the object unless the object has been modified more recently than a certain time.

A nonzero value gives a time as the number of milliseconds since January 1, 1970, GMT. The object is fetched only if it has been modified more recently than that time.

This variable is set by the setIfModifiedSince method. Its value is returned by the getIfModifiedSince method.

The default value of this field is 0, indicating that the fetching must always occur.

url

protected var url: URL!

The URL represents the remote object on the World Wide Web to which this connection is opened.

The value of this field can be accessed by the getURL method.

The default value of this variable is the value of the URL argument in the URLConnection constructor.

useCaches

protected var useCaches: Boolean

If true, the protocol is allowed to use caching whenever it can. If false, the protocol must always try to get a fresh copy of the object.

This field is set by the setUseCaches method. Its value is returned by the getUseCaches method.

Its default value is the value given in the last invocation of the setDefaultUseCaches method.