ZCONFIG(3)

NAME
zconfig - work with config files written in rfc.zeromq.org/spec:4/ZPL.

SYNOPSIS

//  This is a stable class, and may not change except for emergencies. It
//  is provided in stable builds.
//
typedef int (zconfig_fct) (
    zconfig_t *self, void *arg, int level);
//  Create new config item
CZMQ_EXPORT zconfig_t *
    zconfig_new (const char *name, zconfig_t *parent);
//  Load a config tree from a specified ZPL text file; returns a zconfig_t
//  reference for the root, if the file exists and is readable. Returns NULL
//  if the file does not exist.
CZMQ_EXPORT zconfig_t *
    zconfig_load (const char *filename);
//  Equivalent to zconfig_load, taking a format string instead of a fixed
//  filename.
CZMQ_EXPORT zconfig_t *
    zconfig_loadf (const char *format, ...) CHECK_PRINTF (1);
//  Destroy a config item and all its children
CZMQ_EXPORT void
    zconfig_destroy (zconfig_t **self_p);
//  Return name of config item
CZMQ_EXPORT char *
    zconfig_name (zconfig_t *self);
//  Return value of config item
CZMQ_EXPORT char *
    zconfig_value (zconfig_t *self);
//  Insert or update configuration key with value
CZMQ_EXPORT void
    zconfig_put (zconfig_t *self, const char *path, const char *value);
//  Equivalent to zconfig_put, accepting a format specifier and variable
//  argument list, instead of a single string value.
CZMQ_EXPORT void
    zconfig_putf (zconfig_t *self, const char *path, const char *format, ...) CHECK_PRINTF (3);
//  Get value for config item into a string value; leading slash is optional
//  and ignored.
CZMQ_EXPORT char *
    zconfig_get (zconfig_t *self, const char *path, const char *default_value);
//  Set config item name, name may be NULL
CZMQ_EXPORT void
    zconfig_set_name (zconfig_t *self, const char *name);
//  Set new value for config item. The new value may be a string, a printf
//  format, or NULL. Note that if string may possibly contain '%', or if it
//  comes from an insecure source, you must use '%s' as the format, followed
//  by the string.
CZMQ_EXPORT void
    zconfig_set_value (zconfig_t *self, const char *format, ...) CHECK_PRINTF (2);
//  Find our first child, if any
CZMQ_EXPORT zconfig_t *
    zconfig_child (zconfig_t *self);
//  Find our first sibling, if any
CZMQ_EXPORT zconfig_t *
    zconfig_next (zconfig_t *self);
//  Find a config item along a path; leading slash is optional and ignored.
CZMQ_EXPORT zconfig_t *
    zconfig_locate (zconfig_t *self, const char *path);
//  Locate the last config item at a specified depth
CZMQ_EXPORT zconfig_t *
    zconfig_at_depth (zconfig_t *self, int level);
//  Execute a callback for each config item in the tree; returns zero if
//  successful, else -1.
CZMQ_EXPORT int
    zconfig_execute (zconfig_t *self, zconfig_fct handler, void *arg);
//  Add comment to config item before saving to disk. You can add as many
//  comment lines as you like. If you use a null format, all comments are
//  deleted.
CZMQ_EXPORT void
    zconfig_set_comment (zconfig_t *self, const char *format, ...) CHECK_PRINTF (2);
//  Return comments of config item, as zlist.
CZMQ_EXPORT zlist_t *
    zconfig_comments (zconfig_t *self);
//  Save a config tree to a specified ZPL text file, where a filename
//  "-" means dump to standard output.
CZMQ_EXPORT int
    zconfig_save (zconfig_t *self, const char *filename);
//  Equivalent to zconfig_save, taking a format string instead of a fixed
//  filename.
CZMQ_EXPORT int
    zconfig_savef (zconfig_t *self, const char *format, ...) CHECK_PRINTF (2);
//  Report filename used during zconfig_load, or NULL if none
CZMQ_EXPORT const char *
    zconfig_filename (zconfig_t *self);
//  Reload config tree from same file that it was previously loaded from.
//  Returns 0 if OK, -1 if there was an error (and then does not change
//  existing data).
CZMQ_EXPORT int
    zconfig_reload (zconfig_t **self_p);
//  Load a config tree from a memory chunk
CZMQ_EXPORT zconfig_t *
    zconfig_chunk_load (zchunk_t *chunk);
//  Save a config tree to a new memory chunk
CZMQ_EXPORT zchunk_t *
    zconfig_chunk_save (zconfig_t *self);
//  Load a config tree from a null-terminated string
//  Caller owns return value and must destroy it when done.
CZMQ_EXPORT zconfig_t *
    zconfig_str_load (const char *string);
//  Save a config tree to a new null terminated string
//  Caller owns return value and must destroy it when done.
CZMQ_EXPORT char *
    zconfig_str_save (zconfig_t *self);
//  Return true if a configuration tree was loaded from a file and that
//  file has changed in since the tree was loaded.
CZMQ_EXPORT bool
    zconfig_has_changed (zconfig_t *self);
//  Print the config file to open stream
CZMQ_EXPORT void
    zconfig_fprint (zconfig_t *self, FILE *file);
//  Print properties of object
CZMQ_EXPORT void
    zconfig_print (zconfig_t *self);
//  Self test of this class
CZMQ_EXPORT void
    zconfig_test (bool verbose);
Please add '@interface' section in './../src/zconfig.c'.

DESCRIPTION

Lets applications load, work with, and save configuration files. This implements rfc.zeromq.org/spec:4/ZPL, which is a simple structured text format for configuration files.

Here is an example ZPL stream and corresponding config structure:

    context
        iothreads = 1
        verbose = 1      #   Ask for a trace
    main
        type = zqueue    #  ZMQ_DEVICE type
        frontend
            option
                hwm = 1000
                swap = 25000000     #  25MB
            bind = 'inproc://addr1'
            bind = 'ipc://addr2'
        backend
            bind = inproc://addr3

    root                    Down = child
    |                     Across = next
    v
    context-->main
    |         |
    |         v
    |       type=queue-->frontend-->backend
    |                      |          |
    |                      |          v
    |                      |        bind=inproc://addr3
    |                      v
    |                    option-->bind=inproc://addr1-->bind=ipc://addr2
    |                      |
    |                      v
    |                    hwm=1000-->swap=25000000
    v
    iothreads=1-->verbose=false

EXAMPLE

From zconfig_test method.

    //  Create temporary directory for test files
    #   define TESTDIR ".test_zconfig"
    zsys_dir_create (TESTDIR);
    zconfig_t *root = zconfig_new ("root", NULL);
    assert (root);
    zconfig_t *section, *item;
    section = zconfig_new ("headers", root);
    assert (section);
    item = zconfig_new ("email", section);
    assert (item);
    zconfig_set_value (item, "some@random.com");
    item = zconfig_new ("name", section);
    assert (item);
    zconfig_set_value (item, "Justin Kayce");
    zconfig_putf (root, "/curve/secret-key", "%s", "Top Secret");
    zconfig_set_comment (root, "   CURVE certificate");
    zconfig_set_comment (root, "   -----------------");
    assert (zconfig_comments (root));
    zconfig_save (root, TESTDIR "/test.cfg");
    zconfig_destroy (&root);
    root = zconfig_load (TESTDIR "/test.cfg");
    if (verbose)
        zconfig_save (root, "-");
    assert (streq (zconfig_filename (root), TESTDIR "/test.cfg"));
    char *email = zconfig_get (root, "/headers/email", NULL);
    assert (email);
    assert (streq (email, "some@random.com"));
    char *passwd = zconfig_get (root, "/curve/secret-key", NULL);
    assert (passwd);
    assert (streq (passwd, "Top Secret"));
    zconfig_savef (root, "%s/%s", TESTDIR, "test.cfg");
    assert (!zconfig_has_changed (root));
    int rc = zconfig_reload (&root);
    assert (rc == 0);
    assert (!zconfig_has_changed (root));
    zconfig_destroy (&root);
    //  Test chunk load/save
    root = zconfig_new ("root", NULL);
    assert (root);
    section = zconfig_new ("section", root);
    assert (section);
    item = zconfig_new ("value", section);
    assert (item);
    zconfig_set_value (item, "somevalue");
    zconfig_t *search = zconfig_locate (root, "section/value");
    assert (search == item);
    zchunk_t *chunk = zconfig_chunk_save (root);
    assert (strlen ((char *) zchunk_data (chunk)) == 32);
    char *string = zconfig_str_save (root);
    assert (string);
    assert (streq (string, (char *) zchunk_data (chunk)));
    free (string);
    assert (chunk);
    zconfig_destroy (&root);
    root = zconfig_chunk_load (chunk);
    assert (root);
    char *value = zconfig_get (root, "/section/value", NULL);
    assert (value);
    assert (streq (value, "somevalue"));
    //  Test config can't be saved to a file in a path that doesn't
    //  exist or isn't writable
    rc = zconfig_savef (root, "%s/path/that/doesnt/exist/%s", TESTDIR, "test.cfg");
    assert (rc == -1);
    zconfig_destroy (&root);
    zchunk_destroy (&chunk);
    //  Delete all test files
    zdir_t *dir = zdir_new (TESTDIR, NULL);
    assert (dir);
    zdir_remove (dir, true);
    zdir_destroy (&dir);

AUTHORS

The czmq manual was written by the authors in the AUTHORS file.

RESOURCES

Main web site:

Report bugs to the email <zeromq-dev@lists.zeromq.org[1]>

COPYRIGHT

Copyright (c) the Contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for 0MQ: http://czmq.zeromq.org. This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE included with the czmq distribution.

NOTES

1.  zeromq-dev@lists.zeromq.org
    mailto:zeromq-dev@lists.zeromq.org