FileSystemProvider

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Table of Contents

• File paths vs. URIs
  • Coupling with tree nodes
• Operations for Extenders
  • Get entries of a USS folder, PDS or Job
  • Retrieve contents for resources
  • Get statistics of a resource

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In v3 of Zowe Explorer, we have made an architectural shift from using temporary, on-disk files to using the FileSystemProvider interface provided by VS Code. Starting with v3, the three "core" tree views in Zowe Explorer will use implementations of the FileSystemProvider to encapsulate remote operations (reading/writing, renaming, deleting, etc.):

Tree view	FileSystemProvider implementation
Data Sets	DatasetFSProvider
Jobs	JobsFSProvider
Unix System Services (USS)	UssFSProvider

We will no longer write files to the temporary, on-disk directory that was created for previous versions.

We have also exposed a BaseProvider class in Zowe Explorer API to help extenders create their own FileSystemProvider implementations if needed.
However, the implementations above are not directly accessible through Zowe Explorer API. Extenders should use the vscode.workspace.fs façade to access information instead.

File paths vs. URIs

The FileSystemProvider interface largely operates on the concept of resource URIs. Our FileSystemProvider implementations leverage these URIs to build a path structure for the providers to operate. Note that each segment is important when building correct URIs for Zowe Explorer resources.

All core resource URIs for Zowe Explorer use this general structure:

zowe-*:/<Profile Name (LPAR)>/<Resource Path>

Where zowe-* is a scheme that starts with the zowe- prefix. The core schemes are exposed in Zowe Explorer API as the ZoweScheme enum and are defined as the following:

• Data Sets: zowe-ds
• Jobs: zowe-jobs
• USS: zowe-uss

Data Set URIs

For a sequential data set named FRUIT.CHKLIST on the food.zosmf LPAR, the URI would read as follows:

zowe-ds:/food.zosmf/FRUIT.CHKLIST

Partitioned data sets are interpreted as directories in the FileSystemProvider, and members are entries inside the directory.
For example, to represent the member APPLE in PDS FRUIT.BASKET on the food.zosmf LPAR, the URI would be:

zowe-ds:/food.zosmf/FRUIT.BASKET/APPLE

USS URIs

USS URIs use the format zowe-uss:/<Profile Name (LPAR)>/<USS Path> to represent files or folders.
A file at path /u/users/fruit/apple.txt on the food.zosmf LPAR would look like this:

zowe-uss:/food.zosmf/u/users/fruit/apple.txt

It's parent folder, /u/users/fruit/ would look like this:

zowe-uss:/food.zosmf/u/users/fruit/

Job URIs

Job URIs use the format zowe-jobs:/<Profile Name (LPAR)>/<Job ID>/. Spool URIs use the format zowe-jobs:/<Profile Name (LPAR)>/<Job ID>/<Unique Spool ID>.

Extenders can leverage the buildUniqueSpoolName function in Zowe Explorer API to help build spool URIs. The Job ID segment matches the jobid parameter on the IJobFile object.

Coupling with tree nodes

When instantiating a VS Code TreeItem, each item can be paired with a resourceUri to establish a relationship between the URI and the tree node. We recommend that extenders pair their URIs alongside their tree nodes so the resource is easily accessible and so that updates to the URI are reflected in the tree view (such as when a URI is deleted from a provider).

Operations for Extenders

Please note that all of these operations assume that the given resource URI exists in the FileSystemProvider. If the resource does not exist, an exception may be thrown - these should be caught and handled by your extension as needed.

Get statistics of a resource

To retrieve statistics for a resource URI, use the vscode.workspace.fs.stat function.

• Returns a FileStat object containing metadata about the URI, such as its type, size, and timestamps.
  • For USS files and Data Sets, this also contains e-tag and encoding information
  • For Jobs, this contains the IJob or IJobFile object depending on the resource (job or spool)

Get entries of a USS folder, PDS or Job

To list the contents of a USS directory, PDS, or job specified by a given URI, use the vscode.workspace.fs.readDirectory function.

• Returns an array of tuples, where each tuple represents a child entry in the directory.
• For Jobs, use this to return a list of spool files under a given job URI
• For USS files, use this to a list of files and folders at the given path.
• For Data Sets, use this to get the members for a given PDS.

Retrieve contents for resources

To read the contents of a spool file, data set or USS file, use the vscode.workspace.fs.readFile function.

• Returns a Uint8Array with the contents of the resource.