With the File System add-on, it is possible to read and write files (even incrementally), and to read and create directories.

Common Tasks Using the File System Adapter

Find below a table listing some common tasks you can use the File System Adapter for, and which action to use for which task.

Task	Action	Mode	Important Parameters	Comments
Write a complete file in one action.	write			If the file exists, it will be overwritten. If the file does not exist, it will be created.
Replace part of a file.	write		position	Writes the data to the file beginning at the specified position. If the file does not exists you'll get the exception FSADM/8 (see Catching Errors).
Append data to a file.	append	append		If the file exists, the given data will be appended. If the file does not exist, it will be created.
Write a complete file line by line.	append	overwrite		Use mode overwrite for all appends. If the file exists, it will be overwritten. If the file does not exist, it will be created. overwrite will only be applied to the first append. All subsequent appends (e.g. in a loop) automatically get mode append.
Copy a complete file.	copy Runtime 2020.4 Builder 7.8.0			Copy a file in one action. Using copy you can even copy huge files because it does not load the complete file into memory.
Manipulate a file and process the file further (e.g. moving it).	write or append close further processing			Before processing the file further (e.g. moving it), close the file. Otherwise it may be locked.

Static versus Dynamic Requests

We distinct between static and dynamic requests.

Static means that the whole backend information (path and name) is defined in the component diagram and is not modified when called within an action. However, this information can be accessed within an action via the so called deployment macros. This is sometimes useful, e. g. when URL parameters must be calculated or known at runtime only (for details refer to Deployment Macros).
A dynamic call means that the necessary parameters are being specified during the execution of the activity. In the present case, a dynamic usage of the file system adapter means that parameters like the name of a file or a directory are not part of the component diagram, but rather specified in an action and passed on to the file system adapter as an input object. Read more on dynamic file system access on Dynamic File Access.

All errors thrown by the File System adapter can be caught as described in Catching Errors.