# File System Layout

It is important that files are well placed and named within Cacti's directory
structure. The naming structure may contain a **category token** and/or an
**action**.

## Token

Under each category directory, functions should be broken out into multiple
files where applicable. All files must begin with the name of category (ie. its
parent directory name). Valid token names are

* auth
* data_input (maybe rename to script)
* data_query
* data_source
* data_template
* device (rename from host)
* device_template
* event (if we have event management in core)
* graph
* graph_template
* graph_tree
* package
* plugin
* poller
* preset (colors, cdefs, etc, better than data_preset)
* rra
* site
* user

## Actions

This part should reflect what type of actions the file contains. Specific
examples are listed below.

* info - reads information
* update - writes (or changes) information
* form - draws form-related information
* execute - performs some action that does not modify or return information
* utility - contains miscellaneous functions

## Function Verbs

Functions in those PHP modules shall name their token and shall contain a verb
to explain the purpose. Specific examples are listed below.

* list
* get
* save
* copy
* clear
* remove
* update

## access/

Directly under the `access/` directory are sub directories for ajax related
calls and javascript includes for web interface functionality.

## cli/

`[token]_[action].php`

## images/

* icons/        # 16x16, 32x32 icons
* buttons/      # button images (save, cancel, etc)
* tabs/         # tab images

## include/

Code that must be accessed globally but is not contained inside of a function
should be stored in the `include/` directory. The most common examples are to
store globally accessible constants and arrays.

Directly under the `include/` directory, the files beginning with `global` are
used to store information that is accessible everywhere in the code. Only store
information in these files that are meaningful to the entire program. Also
under the `include/` directory is a directory for each category (graph, device,
etc), where information specific to that category is to be stored.

Constants that are made available everyone in the program

```markdown
include/global_constants.php
```

Arrays that are only used with graphs

```markdown
include/graph/graph_arrays.php
```

```markdown
  js/                                   # javascript files
    jquery/                             # jquery dist
    jscalendar/                         # jscalendar dist
    jstree/                             # treeview control
    zoom.js
  html/                                 # contains mostly html
    template/                           # base html template includes
      page_header.php
      page_graph_header.php
      page_footer
  css/
    jquery/
    main.css                            # global css only
    form.css                            # css for drawing forms
    graph.css                           # css for graph viewing
  [token]/                              # token specific includes
    [token]_arrays.php
    [token]_form.php
    [token]_constants.php
  config.php
  global.php
  global_arrays.php
  global_constants.php
  global_form.php
  global_languge.php
  global_settings.php
```

## lib/

Functions that must be accessed globally should be stored in the ''lib/''
directory. This is where most of the heavy lifting in Cacti occurs.

Directly under the `lib/` directory, the files beginning with `api` are generic
wrappers that are only to be used by third party developers. These files simply
include the contents of the various subdirectories under `lib/` to make
developers' lives easier. Also under the `lib/` directory is a directory for
each category (graph, device, etc), where functions specific to that category
are to be stored. The `lib/sys/` directory is a special category that is meant
to store Cacti internal functions that are not to be made available directly
within the API.

API wrapper for graph-related functions

```markdown
lib/api_graph.php
```

Functions that update information about devices

```markdown
lib/device/device_update.php
```

Functions that read information about data templates

```markdown
lib/data_template/data_template_info.php
```

```markdown
  adodb/                                # adodb dist
  sys/                                  # internal libraries (snmp, database, etc)
  [token]/
     [token]_form.php
     [token]_info.php
     [token]_update.php
     [token]_ajax.php
  api_[token].php
```

## locales/

## plugins/

Directly under the `plugins/` directory are sub directories that contain
plugins for Cacti.

### Including and Requiring Files

To reduce bloat, each file and/or function should include any and all files
which it relies on.

The following function directly relies the libraries related to sequences and
reading graph information. The `require_once` directive is used instead of
`require` to prevent PHP re-declaration errors.

```php
function api_graph_item_save($graph_item_id, &$_fields_graph_item) {
    require_once(CACTI_BASE_PATH . '/lib/sys/sequence.php');
    require_once(CACTI_BASE_PATH . '/lib/graph/graph_info.php');
```