6.0.0-git
2018-12-17
Last Modified 2013-02-04 by Jan Schneider

Horde_Argv

Advanced Usage

This is reference documentation. If you haven't read the Basic Usage tutorial document yet, do so now.

Creating and populating the parser

There are several ways to populate the parser with options. One way is to pass a list of Horde_Argv_Options to the Horde_Argv_Parser constructor:

$parser = new Horde_Argv_Parser(array('optionList' => array(
    new Horde_Argv_Option(
        '-f', '--filename',
        array('action' => 'store', 'type' => 'string', 'dest' => 'filename')),
    new Horde_Argv_Option(
        '-q', '--quiet',
        array('action' => 'store_false', 'dest' => 'verbose'))
)));

For long option lists, it's often more convenient/readable to create the list separately:

$option_list = array(
    new Horde_Argv_Option(
        '-f', '--filename',
        array('action' => 'store', 'type' => 'string', 'dest' => 'filename')),
    // ... 17 other options ...
    new Horde_Argv_Option(
        '-q', '--quiet',
        array('action' => 'store_false', 'dest' => 'verbose'))
);
$parser = new Horde_Argv_Parser(array('optionList' => $option_list));

Or, you can use the addOption() method of Horde_Argv_Parser to add options one at a time:

$parser = new Horde_Argv_Parser();
$parser->addOption(
    '-f', '--filename',
    array('action' => 'store', 'type' => 'string', 'dest' => 'filename')
);
$parser->addOption(
    '-q', '--quiet',
    array('action' => 'store_false', 'dest' => 'verbose')
);

This method makes it easier to track down exceptions raised by the Horde_Argv_Option constructor, which are common because of the complicated interdependencies among the various keyword arguments -- if you get it wrong, Horde_Argv throws an InvalidArgumentException.

addOption() can be called in one of two ways:

  • pass it an Horde_Argv_Option instance
  • pass it any combination of positional and keyword arguments that are acceptable to new Horde_Argv_Option() (ie., to the Horde_Argv_Option constructor), and it will create the Horde_Argv_Option instance for you (shown above)

Defining options

Each Horde_Argv_Option instance represents a set of synonymous command-line options, ie. options that have the same meaning and effect, but different spellings. You can specify any number of short or long option strings, but you must specify at least one option string.

To define an option with only a short option string:

new Horde_Argv_Option('-f', ...)

And to define an option with only a long option string:

new Horde_Argv_Option('--foo', ...)

The ... represents a set of keyword arguments that define option attributes, i.e. attributes of the Horde_Argv_Option object. Just which keyword args you must supply for a given Horde_Argv_Option is fairly complicated (see the various _check*() methods in the Horde_Argv_Option class if you don't believe me). If you get it wrong, Horde_Argv throws an InvalidArgumentException explaining your mistake.

The most important attribute of an option is its action, ie. what to do when we encounter this option on the command-line. The possible actions are:

store
store this option's argument [default]
store_const
store a constant value
store_true
store a TRUE value
store_false
store a FALSE value
append
append this option's argument to a list
count
increment a counter by one
callback
call a specified function
help
print a usage message including all options and the documentation for them

(If you don't supply an action, the default is store. For this action, you may also supply type and dest option attributes; see below.)

As you can see, most actions involve storing or updating a value somewhere. Horde_Argv always creates an instance of Horde_Argv_Values (referred to as options) specifically for this purpose. Option arguments (and various other values) are stored as attributes of this object, according to the dest (destination) option attribute.

For example, when you call

$parser->parseArgs();

one of the first things Horde_Argv does is create the options object:

$options = new Horde_Argv_Values();

If one of the options in this parser is defined with

new Horde_Argv_Option('-f', '--file', array('action' => 'store', 'type' => 'string', 'dest' => 'filename'))

and the command-line being parsed includes any of the following:

-ffoo
-f foo
--file=foo
--file foo

then Horde_Argv, on seeing the "-f" or "--file" option, will do the equivalent of this:

$options->filename = 'foo';

Clearly, the type and dest arguments are almost as important as action. action is the only attribute that is meaningful for all options, though, so it is the most important.

Option actions

The various option actions all have slightly different requirements and effects. Most actions have several relevant option attributes which you may specify to guide Horde_Argv's behaviour; a few have required attributes, which you must specify for any option using that action.

  • store [relevant: type, dest, nargs, choices]
The option must be followed by an argument, which is converted to a value according to type and stored in dest. If nargs > 1, multiple arguments will be consumed from the command line; all will be converted according to type and stored to dest as an array. See the "Option types" section below.

If choices is supplied (an array of strings), the type defaults to choice.

If type is not supplied, it defaults to string.

If dest is not supplied, Horde_Argv derives a destination from the first long option strings (e.g., "--foo-bar" implies "foo_bar"). If there are no long option strings, Horde_Argv derives a destination from the first short option string (e.g., "-f" implies "f").

Example:

$parser->addOption('-f');
$parser->addOption('-p', array('type' => 'float', 'nargs' => 3, 'dest' => 'point'));
Given the following command line:

-f foo.txt -p 1 -3.5 4 -fbar.txt

Horde_Argv will set

$options->f = 'foo.txt';
$options->point = array(1.0, -3.5, 4.0);
$options->f = 'bar.txt';
  • store_const [required: const; relevant: dest]
The value const is stored in dest.

Example:

$parser->addOption('-q', '--quiet', array('action' => 'store_const', 'const' => 0, 'dest' => 'verbose'));
$parser->addOption('-v', '--verbose', array('action' => 'store_const', 'const' => 1, 'dest' => 'verbose'));
$parser->addOption('--noisy', array('action' => 'store_const', 'const' => 2, 'dest' => 'verbose'));
If "--noisy" is seen, Horde_Argv will set

$options->verbose = 2;
  • store_true [relevant: dest]
A special case of store_const that stores a TRUE value to dest.
  • store_false [relevant: dest]
Like store_true, but stores a FALSE value.

Example:

$parser->addOption(null, '--clobber', array('action' => 'store_true', 'dest' => 'clobber'));
$parser->addOption(null, '--no-clobber', array('action' => 'store_false', 'dest' => 'clobber'));
  • append [relevant: type, dest, nargs, choices]
The option must be followed by an argument, which is appended to the array in dest. If no default value for dest is supplied, an empty array is automatically created when Horde_Argv first encounters this option on the command-line. If nargs > 1, multiple arguments are consumed, and an array of length nargs is appended to dest.

The defaults for type and dest are the same as for the store action.

Example:

$parser->addOption('-t', '--tracks', array('action' => 'append', 'type' => 'int'));
If "-t3" is seen on the command-line, Horde_Argv does the equivalent of:

$options->tracks = array();
$options->tracks[] = intval('3');
If, a little later on, "--tracks=4" is seen, it does:

$options->tracks[] = intval('4');
  • count [relevant: dest]
Increment the integer stored at dest. dest is set to zero before being incremented the first time (unless you supply a default value).

Example:

$parser->addOption('-v', array('action' => 'count', 'dest' => 'verbosity'));
The first time "-v" is seen on the command line, Horde_Argv does the equivalent of:

$options->verbosity = 0;
$options->verbosity += 1;
Every subsequent occurrence of "-v" results in

$options->verbosity += 1;
  • callback [required: callback; relevant: type, nargs, callback_args, callback_kwargs]
Call the function specified by callback. The signature of this function should be

func(Horde_Argv_Option $option,
     string $opt,
     mixed $value,
     Horde_Argv_Parser $parser,
     array $args,
     array $kwargs)
See Option Callbacks for more detail.
  • help [relevant: none]
Prints a complete help message for all the options in the current option parser. The help message is constructed from the usage string passed to Horde_Argv_Parser's constructor and the help string passed to every option.

If no help string is supplied for an option, it will still be listed in the help message. To omit an option entirely, use the special value Horde_Argv_Option::SUPPRESS_HELP.

Example:

$parser = new Horde_Argv_Parser();
$parser->addOption('-h', '--help',
                   array('action' => 'help'));
$parser->addOption('-v',
                   array('action' => 'store_true', 'dest' => 'verbose',
                         'help' => 'Be moderately verbose'));
$parser->addOption('--file',
                   array('dest' => 'filename',
                         'help' => 'Input file to read data from'));
$parser->addOption('--secret',
                   array('help' => Horde_Argv_Option::SUPPRESS_HELP));
If Horde_Argv sees either "-h" or "--help" on the command line, it will print something like the following help message to stdout (assuming $_SERVER['argv'][0] is "foo.php"):

usage: foo.py [options]

options:
  -h, --help        Show this help message and exit
  -v                Be moderately verbose
  --file=FILENAME   Input file to read data from
After printing the help message, Horde_Argv terminates your process with exit(0).
  • version [relevant: none]
Prints the version number supplied to the Horde_Argv_Parser to stdout and exits. The version number is actually formatted and printed by the printVersion() method of Horde_Argv_Parser. Generally only relevant if the version argument is supplied to the Horde_Argv_Parser constructor.

Option types

Horde_Argv has six built-in option types: string, int, long, choice, float and complex. If you need to add new option types, see Extending Horde_Argv.

Arguments to string options are not checked or converted in any way: the text on the command line is stored in the destination (or passed to the callback) as-is.

Integer arguments are passed to intval() to convert them to PHP integers. If intval() fails, so will Horde_Argv, although with a more useful error message. (Internally, Horde_Argv throws Horde_Argv_OptionValueException from Horde_Argv_Option#checkBuiltin(); Horde_Argv_Parser catches this exception higher up and terminates your program with a useful error message.)

Likewise, float arguments are passed to floatval() for conversion, long arguments also to intval(), and complex arguments are not handled yet. Apart from that, they are handled identically to integer arguments.

choice options are a subtype of string options. The choices option attribute (an array of strings) defines the set of allowed option arguments. Horde_Argv_Option#checkChoice() compares user-supplied option arguments against this master list and throws Horde_Argv_OptionValueException if an invalid string is given.

Querying and manipulating your option parser

Sometimes, it's useful to poke around your option parser and see what's there. Horde_Argv_Parser provides a couple of methods to help you out:

boolean hasOption(string $opt_str)
Given an option string such as "-q" or "--verbose", returns true if the Horde_Argv_Parser has an option with that option string.
Horde_Argv_Option getOption(string $opt_str)
Returns the Horde_Argv_Option instance that implements the supplied option string, or null if no options implement it.
removeOption(string $opt_str)
If the Horde_Argv_Parser has an option corresponding to $opt_str, that option is removed. If that option provided any other option strings, all of those option strings become invalid. If $opt_str does not occur in any option belonging to this Horde_Argv_Parser, throws InvalidArgumentException.

Conflicts between options

If you're not careful, it's easy to define conflicting options:

$parser->addOption('-n', '--dry-run', ...);
[...]
$parser->addOption('-n', '--noisy', ...);

(This is even easier to do if you've defined your own Horde_Argv_Parser subclass with some standard options.)

Every time you add an option, Horde_Argv checks for conflicts with existing options. If it finds any, it invokes the current conflict-handling mechanism. You can set the conflict-handling mechanism either in the constructor:

$parser = new Horde_Argv_Parser(..., array('conflictHandler' => '...'));

or with a separate call:

$parser->setConflictHandler('...');

The available conflict-handling mechanisms are:

error (default)
assume option conflicts are a programming error and throws Horde_Argv_OptionConflictException
resolve
resolve option conflicts intelligently (see below)

Here's an example: first, define an Horde_Argv_Parser that resolves conflicts intelligently:

$parser = new Horde_Argv_Parser(array('conflictHandler' => 'resolve'));

Now add all of our options:

$parser->addOption('-n', '--dry-run', ..., array('help' => 'original dry-run option'));
[...]
$parser->addOption('-n', '--noisy', ..., array('help' => 'be noisy'));

At this point, Horde_Argv detects that a previously-added option is already using the "-n" option string. Since conflictHandler is "resolve", it resolves the situation by removing "-n" from the earlier option's list of option strings. Now, "--dry-run" is the only way for the user to activate that option. If the user asks for help, the help message will reflect that, e.g.:

options:
  --dry-run     original dry-run option
  [...]
  -n, --noisy   be noisy

Note that it's possible to whittle away the option strings for a previously-added option until there are none left, and the user has no way of invoking that option from the command-line. In that case, Horde_Argv removes that option completely, so it doesn't show up in help text or anywhere else. E.g. if we carry on with our existing Horde_Argv_Parser:

$parser->addOption('--dry-run', ..., array('help' => 'new dry-run option'));

At this point, the first "-n/--dry-run" option is no longer accessible, so Horde_Argv removes it. If the user asks for help, they'll get something like this:

options:
  [...]
  -n, --noisy   be noisy
  --dry-run     new dry-run option