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With the URL adapter, it is possible to get and put messages via the FTP protocol. The input and output of this adapter is always of type Blob to support all possible data types (e.g. binary for images, text with HTML code, XML messages, etc.).

FTP commands like RNFR, RNTO, etc. are also supported (see also http://www.faqs.org/rfcs/rfc959.html).

Differences between FTP, FTPS, and SFTP

A lot of times these protocols get confused and mixed up due to the similarity in function and names. The Bridge supports the following file transfer protocols:

FTPFTPSSFTP
File Transfer ProtocolFTP Secure and FTP-SSLSSH File Transfer Protocol
Classic insecure FTPFTP over TLS/SSLExtension of SSH
Plain FTPPlain FTP over TLS/SSL channelHas nothing in common with original FTP
Username and password are sent as clear text over the networkUser name and password are encryptedUser name and password are encrypted
Transfer is not encryptedTransfer is encryptedTransfer is encrypted
Uses TCP port 21Uses TCP port 21 or 990Uses TCP port 22

FTP via SSH is not supported by the Bridge.

Transfer Mode

The transfer mode by default is set to binary, only the list command is transferred in ASCII mode.

In order to change the transfer mode, use the cURL option CURLOPT_QUOTE (see chapter Setting cURL Options on the URL Adapter). Using this option, the transfer mode is changed before any method is executed. Using the command TYPE Ib in the command array, these commands are executed after any method like put, get, or list.

Streaming FTP

When reading or writing files, the examples load the whole file into memory. This might cause problems if these files are big.

In order to avoid consuming too much memory the URL adapter offers the option to read and write data in little chunks. This mechanism is called streaming, since, after reading a small data chunk from the FTP server, it is immediately written to a file before doing the next read. For sending data, the mechanism works analogously. The above example model contains a use case File Streaming that shows how to receive and send big files without using much memory.

Tagged Values

Find below a list of relevant tagged values, if the URL adapter is used with the FTP protocol.
Default values used when an option is not explicitly set are written in bold.

Tagged ValueDescriptionValues
protocolTransport protocol.ftp
methodFTP method.GET, POST, PUT, LIST (PUT will internally be to POST)
portMachine port number the service is binding to. This port number can be given at service level only.21
pathFTP path for the request.
Advanced
optionsNative cURL options.cURL Options
Authentication
userUsername/password.
Proxy
proxyTypeType of the proxy.HTTP, SOCKS5
proxyURLURL of the proxy server.
proxyUserProxy user.
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