Copyright © 2005-2018 MultiMedia Soft

Downloader.SessionStartToMemory method

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Remarks

 

Starts a download session of a remote file pointed by a URL and stores the downloaded file inside a given memory buffer.

The size of the memory buffer needed to store the full remote file can be obtained through the Downloader.SessionDataSizeGet method.

 

A successful call to this method allows the container application the be notified about the advancement through the CallbackForDownloaderEvents delegate which is invoked with the nEvent parameter set to one of the following values:

 

- the EV_DOWNLOADER_SESSION_STARTED event reports that the downloading session is started

- the EV_DOWNLOADER_SESSION_PROGRESS event informs about the download advancement expressed in percentage

- the EV_DOWNLOADER_SESSION_COMPLETED event reports that the downloading session is completed successfully

 

In case the connection to the remote server or the access to the remote file should fail, the CallbackForDownloaderEvents delegate is invoked with the nEvent parameter set to EV_DOWNLOADER_SESSION_FAILED.

 

In case the connection should be stopped by the user through a call to the Downloader.SessionStop method, the CallbackForDownloaderEvents delegate is invoked with the nEvent parameter set to EV_DOWNLOADER_SESSION_STOPPED.

 

For details about management of download sessions from HTTP and FTP servers, refer to the How to manage download sessions tutorial.

 

 

Syntax

 

[Visual Basic]

Public Function SessionStartToMemory (

strURL as String,

strUsername as String,

strPassword as String,

pBuffer() as Byte,

nBufferLength as Int32,

bDisableCache as Boolean

) as Int32


 

[C#]

public Int32 SessionStartToMemory (

string strURL,

string strUsername,

string strPassword,

byte[] pBuffer,

Int32 nBufferLength,

bool bDisableCache

);


 

[C++]

public: Int32 SessionStartToMemory(

string strURL,

string strUsername,

string strPassword,

unsigned char __gc[] pBuffer,

Int32 nBufferLength,

bool bDisableCache

);


 

 

Parameter

Description

 

 

strURL

String containing the URL pointing to the remote media file to download. Accepted Internet protocols for the passed URL must be of type HTTP or FTP.

strUsername

String containing the username for accessing the server. Leave the string empty if the directory containing the remote file is not username protected.

strPassword

String containing the password for accessing the server. Leave the string empty if the directory containing the remote file is not password protected.

pBuffer

Memory buffer where contents of the downloaded file will be stored.

The buffer must be previously allocated by the caller using the size obtained through a previous call to the Downloader.SessionDataSizeGet method.

When the buffer is no more needed, its deallocation is responsibility of the caller.

nBufferLength

Length in bytes of the given buffer.

bDisableCache

Flag for determining if the usage of the Internet cache must be disabled or not.

Supported values are the following:

Mnemonic constant

Meaning

false

If the file to download is already inside the Internet cache, allows taking the cached file.

true

Never use an eventual cached file, always take it from the remote server.

 

 

Return value

 

Value

Meaning

 

 

Value >= 0

The method call was successful and the returned value is the unique identifier of the download session.

Negative value

An error occurred: see the LastError property for error details or for a list of the possible error values.

In case the error code should be ERR_DOWNLOADER_REMOTE_FILE_FAILURE or ERR_DOWNLOADER_LOCAL_FILE_FAILURE the Downloader.LastFileExceptionGet method would provide the nature of the error which may assume one of the following values:

Value

Meaning

1

An unspecified error occurred.

2

The file could not be located.

3

All or part of the path is invalid.

4

The permitted number of open files was exceeded.

5

The file could not be accessed.

6

There was an attempt to use an invalid file handle.

7

The current working directory cannot be removed.

8

There are no more directory entries.

9

There was an error trying to set the file pointer.

10

There was a hardware error.

11

SHARE.EXE was not loaded, or a shared region was locked.

12

There was an attempt to lock a region that was already locked.

13

The disk is full.

14

The end of file was reached.