Using the URL Adapter with the FTP Protocol and Related Protocols
This page explains the URL Adapter in Bridge context. If you were looking for the same information regarding the PAS Designer, refer to URL Adapter in the Designer guide.
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.).
Example File (Builder project Add-ons/URL):
 | <bridgeDocPath>\Add-ons\URL\uml\urlFtp.xml |
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:
| FTP | FTPS | SFTP |
|---|---|---|
| File Transfer Protocol | FTP Secure and FTP-SSL | SSH File Transfer Protocol |
| Classic insecure FTP | FTP over TLS/SSL | Extension of SSH |
| Plain FTP | Plain FTP over TLS/SSL channel | Has nothing in common with original FTP |
| Username and password are sent as clear text over the network | User name and password are encrypted | User name and password are encrypted |
| Transfer is not encrypted | Transfer is encrypted | Transfer is encrypted |
| Uses TCP port 21 | Uses TCP port 21 or 990 | Uses 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 Value | Description | Values | |
|---|---|---|---|
| protocol | Transport protocol. | ftp | |
| method | FTP method. | GET, POST, PUT, LIST (PUT will internally be to POST) | |
| port | Machine port number the service is binding to. This port number can be given at service level only. | 21 | |
| path | FTP path for the request. | ||
| Advanced | |||
| options | Native cURL options. | cURL Options | |
| Authentication | |||
| user | Username/password. | ||
| Proxy | |||
| proxyType | Type of the proxy. | HTTP, SOCKS5 | |
| proxyURL | URL of the proxy server. | ||
| proxyUser | Proxy user. | ||