[Deprecated] file-cache

Note: This package has been deprecated and will no longer be receiving support updates.


Library to store files locally identified by a hash of the file contents. A sub-directory is created and identified by a hash of the file, the original file is then stored under the hash sub-directory.

The hash is created when writing the binary contents to disk. Each file will generate a unique hash.

``sh
/root-dir
.. /hash
.. / ../original-file.ext
`

Installation

`sh
npm i @bcgov/file-cache
`

Configuration

The root directory for the file cache can be specified by an option (fileCachePath), or an environment variable (FILE\_CACHE\_PATH), or will just use the temp directory as specified by the Operating System.

$3

The default FILE\_CACHE\_PATH will use the Operating System's default temporary directory. However, you may override this behavior with the following:

#### Direct

`js
const FileCache = require('@bcgov/file-cache');
const fileCache = new FileCache({fileCachePath: '/var/usr/file-cache'});
`

#### Environment Variables

`sh
export FILE_CACHE_PATH = '/var/usr/file-cache';
`

`js
const FileCache = require('@bcgov/file-cache');
const fileCache = new FileCache();
`

Usage

$3

Create a new fileCache object, the configured directory will be verified and created if required. Will throw an Error if the directory does not exist and cannot be created.

`js
const FileCache = require('@bcgov/file-cache');
const fileCache = new FileCache({fileCachePath: '/var/usr/file-cache'});
`

$3

Write contents of a buffer to the file cache.

`js
const writeFileResult = await fileCache.write(input.content, input.fileName, 'binary', {overwrite: true});

`

| Parameters | Description |
| --- | --- |
| content | string or buffer of data |
| name | Filename or extension or content. If extension, then UUID will be used for the name: UUID.ext |
| contentEncodingType | Encoding type of content. ex. base64, bin, hex. Default is base64 |
| options | Object for optional work. default is {overwrite = false}. |
| options.overwrite | If true, then allow the destination file to be overwritten if it exists, otherwise will return an error. |

Returns

`json
{
"success": false,
"errorType": null,
"errorMsg": null,
"hash": null
}
`

| Field | Description |
| --- | --- |
| success | boolean, true indicates data written to cache, false otherwise |
| errorType | number - error number if not successful. |
| errorMsg | string - error message if not successful. |
| hash | string - hash/key identifying the file |

$3

Move existing file to file cache.

`js
const moveFileResult = await fileCache.move(req.file.path, req.file.originalname);
`

| Parameters | Description |
| --- | --- |
| source | existing file |
| name | name of file with extension ex. my-word-file.docx |
| options | Object for optional work. default is {overwrite = false}. |
| options.overwrite | If true, then allow the destination file to be overwritten if it exists, otherwise will return an error. |

Returns object

`json
{
"success": false,
"errorType": null,
"errorMsg": null,
"hash": null
}
`

| Field | Description |
| --- | --- |
| success | boolean, true indicates data written to cache, false otherwise |
| errorType | number - error number if not successful. |
| errorMsg | string - error message if not successful. |
| hash | string - hash/key identifying the file |

$3

Read file from cache. Will throw an Error if file not found or error reading from file system.

`js
const cachedFile = await fileCache.read(hash);
`

| Parameters | Description |
| --- | --- |
| hash | string - hash/key for file in cache |

Returns file

See fs.readFile

$3

Find a file in the cache.

`js
const findFileResult = fileCache.find(hash);
`

| Parameters | Description |
| --- | --- |
| hash | string - hash/key for file in cache |

Returns object

`json
{
"success": false,
"errorType": null,
"errorMsg": null,
"hash": null,
"name": null,
"ext": null,
"dir": null,
"path": null
}
`

| Field | Description |
| --- | --- |
| success | boolean, true indicates file found to cache, false otherwise |
| errorType | number - error number if not successful. |
| errorMsg | string - error message if not successful. |
| hash | string - hash/key identifying the file |
| name | name original file. ex. my-word-file.docx |
| ext | extension portion of file name. ex. .docx |
| dir | directory portion of full path (root dir + hash) |
| path | full path to original file in cache |

$3

Remove a file from the cache.

`js
const removeFileResult = await fileCache.remove(hash);
`

| Parameters | Description |
| --- | --- |
| hash | string - hash/key for file in cache |

Returns object

`json
{
"success": false,
"errorType": null,
"errorMsg": null
}
``

| Field | Description |
| --- | --- |
| success | boolean, true indicates file found and removed from cache, false otherwise |
| errorType | number - error number if not successful. |
| errorMsg | string - error message if not successful. |