File Scheme Syntax
To make applications portable, the Application Builder allows you to use virtual file locations using file schemes. A file scheme can be seen as a pointer to a file on the file system, but the application does not need to know where the file is actually stored (this is set in the Preferences window, see below.)
Different file schemes exist for different purposes:
•
The user file scheme is for files that should be persistent between different runs of an application by the same user.
•
The common file scheme behaves in the same way, but is for files that should be shared between all users.
•
The temp file scheme is for files that should be removed as soon as the application is closed.
•
The dbfile file scheme is for file versions that are stored in a Model Manager database.
•
The embedded file scheme is used to store files in the application itself, under Libraries>Files. This can be useful if you want to make the application self-contained and send it to someone else.
•
The upload file scheme is for files that are uploaded to the application by the user at runtime, such as a CAD file or an experimental data file to which the user browses.
The table below summarizes all available file schemes.
Scheme
Refers To
Default Path
Typical Usage
embedded:///
Files embedded in the application under Libraries > Files.
N/A
Experimental data, CAD files, mesh files, experimental data.
upload:///
Files to be uploaded by the user at run time.
Determined by the Target directory in the Settings window of the File declaration
Experimental data, CAD files, mesh files, interpolation data.
temp:///
Files in a random temporary directory, which is unique for each started application instance. These files are deleted when the application is closed.
A random subdirectory to the folder for temporary files, as determined by the settings in Preferences > Files
Temporary files produced by command sequences or methods, or data export to a file saved on the client (for use with COMSOL Server).
user:///
Files in a directory shared by all applications for the current user.
Determined by the settings in Preferences > Files
Output from methods to be saved between sessions.
common:///
Files in a directory shared by all users.
Determined by the settings in Preferences > Files
Files shared between many users or applications.
dbfile:///
File versions stored in a Model Manager database.
N/A
Experimental data, CAD files, mesh files, interpolation data.
For more information on files in the Libraries node accessible by the embedded:/// syntax, see Libraries.
The table below summarizes the usage of the different file schemes. In the table, a check mark means that this scheme is available and (r) means that it is the recommended scheme. The dbfile file scheme is available for all usages.
Usage
embedded
upload
temp
user
common
File is used as input
√ (r)
√
 
 
√
File is output
 
 
√ (r)
√
 
Method reading a file
√ (r)
√
√
√
√
Method writing a file
√
 
√ (r)
√
 
File is client-side
√
√
√ (r)
√
√
You can set the preferences for the paths to temporary, user, and common files in the Files page of the Preferences window, which is accessible from the File menu, as shown in the figure below.
For a COMSOL Multiphysics installation, a typical default location for the user and common folders for a user named paul is:
C:\Users\paul\.comsol\v64\applications\files
For compiled applications, these folders are located within the corresponding COMSOL Runtime folders, for example:
C:\Users\paul\.comsol\v64runtime\applications\files
In the case of compiled apps, the application preferences, accessible from the About dialog, only allow changing the location of the temporary folder temp. The user and common folders are always located within the COMSOL Runtime folder and cannot be relocated.