--- name: "coap_delete_all_resources" section: "3" platform: "linux" package: "libcoap2" version: "4.2.1-1" release: "Debian 11 (Bullseye)" platforms: ["linux"] url: "https://new.carta.tech/coap_resource" --- # coap\_delete\_all\_resources(3) Work with CoAP resources Part of [coap\_resource(3)](/coap_resource/3.md). ## NAME coap\_resource, coap\_resource\_init, coap\_resource\_unknown\_init, coap\_add\_resource, coap\_delete\_resource, coap\_delete\_all\_resources, coap\_resource\_set\_mode - Work with CoAP resources ## SYNOPSIS **#include \** **coap\_resource\_t \*coap\_resource\_init(coap\_str\_const\_t \****uri\_path***, int** *flags***);** **coap\_resource\_t \*coap\_resource\_unknown\_init(coap\_method\_handler\_t** *put\_handler***);** **void coap\_add\_resource(coap\_context\_t \****context***, coap\_resource\_t \****resource***);** **int coap\_delete\_resource(coap\_context\_t** *context***, coap\_resource\_t** *resource***);** **void coap\_delete\_all\_resources(coap\_context\_t \****context***);** **void coap\_resource\_set\_mode(coap\_resource\_t \****resource***, int** *mode***);** Link with **-lcoap-2**, **-lcoap-2-gnutls**, **-lcoap-2-openssl** or **-lcoap-2-tinydtls** depending on your (D)TLS library type. ## DESCRIPTION CoAP Resources on a CoAP Server need to be created and updated etc. The URI in the request packet defines the resource to work with, with possibly the Query referring to a sub-resource. When resources are configured on the CoAP server, the URI to match against in the request packet is specified. Callback Handlers are then added to the resource to handle the different request methods. Adding Attributes allows textual information to be added to the resource which can then be reported back to any client doing a "GET .well-known/core" request. If an incoming packet request matches a resource’s URI and Method, then the appropriate callback resource handler is invoked to process the packet which then should update a suitable response packet for sending back to the requester. There is support for handling incoming packets where the URI is unknown. This could, for example, happen when a PUT request is trying to create a new resource. It is the responsibility of the unknown resource callback handler to either create a new resource for the URI or just manage things separately. CoAP Observe (RFC 7641) is not supported for unknown resources, so a new resource with GET handler must be created by the unknown resource callback handle matching the URI which then can be Observable. The **coap\_resource\_init**() function returns a newly created *resource* of type *coap\_resource\_t* \* . *uri\_path* specifies the uri string path to match against. *flags* is used to define whether the *resource* is of type Confirmable Message or Non-Confirmable Message for any "observe" responses. See [**coap\_observe**(3)](/coap_observe/3.md). *flags* can be one of the following definitions or’ed together. | | | | --- | --- | | **COAP\_RESOURCE\_FLAGS\_NOTIFY\_NON** | Set the notification message type to non-confirmable for any trigggered "observe" responses. | | **COAP\_RESOURCE\_FLAGS\_NOTIFY\_CON** | Set the notification message type to confirmable for any trigggered "observe" responses. | | **COAP\_RESOURCE\_FLAGS\_RELEASE\_URI** | Free off the coap\_str\_const\_t for *uri\_path* when the *resource* is deleted. | **NOTE:** *uri\_path*, if not 7 bit readable ASCII, binary bytes must be hex encoded according to the rules defined in RFC3968 Section 2.1. The **coap\_resource\_unknown\_init**() returns a newly created *resource* of type *coap\_resource\_t* \*. *put\_handler* is automatically added to the *resource* to handle PUT requests to resources that are unknown. Additional handlers can be added to this resource if required. The **coap\_add\_resource**() function registers the given *resource* with the *context*. The *resource* must have been created by **coap\_resource\_init**(), or **coap\_resource\_unknown\_init**(). The storage allocated for the *resource* will be released by **coap\_delete\_resource**(). As the *uri\_path* of the resource has to be unique across all of the resources associated with a *context*, **coap\_add\_resource**() (or **coap\_add\_resource\_release**()) will delete any previous *resource* with the same *uri\_path* before adding in the new *resource*. The **coap\_delete\_resource**() function deletes a *resource* identified by *resource* from *context*. The storage allocated for that *resource* is freed, along with any attrigutes associated with the *resource*. The **coap\_delete\_all\_resources**() function deletes all resources from *context* and frees their storage. The **coap\_resource\_set\_mode**() changes the notification message type of *resource* to the given *mode* which must be one of COAP\_RESOURCE\_FLAGS\_NOTIFY\_NON or COAP\_RESOURCE\_FLAGS\_NOTIFY\_CON. ## RETURN VALUES The **coap\_resource\_init**() and **coap\_resource\_unknown\_init**() functions return a newly created resource or NULL if there is a malloc failure. The **coap\_delete\_resource**() function return 0 on failure (*resource* not found), 1 on success. ## EXAMPLES **Fixed Resources Set Up** ``` #include #define INDEX "This is an example server using libcoap\n" void hnd_get_index(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { unsigned char buf[3]; response->code = COAP_RESPONSE_CODE(205); coap_add_option(response, COAP_OPTION_CONTENT_TYPE, coap_encode_var_safe(buf, sizeof(buf), COAP_MEDIATYPE_TEXT_PLAIN), buf); coap_add_option(response, COAP_OPTION_MAXAGE, coap_encode_var_safe(buf, sizeof(buf), 0x2ffff), buf); coap_add_data(response, strlen(INDEX), (const uint8_t *)INDEX); } void hnd_delete_time(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { /* .. code .. */ } void hnd_get_time(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { /* .. code .. */ } void hnd_put_time(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { /* .. code .. */ } static void init_resources(coap_context_t *ctx) { coap_resource_t *r; /* Create a resource to return general information */ r = coap_resource_init(NULL, 0); coap_register_handler(r, COAP_REQUEST_GET, hnd_get_index); /* Document resource for .well-known/core request */ coap_add_attr(r, coap_make_str_const("ct"), coap_make_str_const("0"), 0); coap_add_attr(r, coap_make_str_const("title"), coap_make_str_const("\"General Info\""), 0); coap_add_resource(ctx, r); /* Create a resource to return return or update time */ r = coap_resource_init(coap_make_str_const("time"), COAP_RESOURCE_FLAGS_NOTIFY_CON); coap_resource_set_get_observable(r, 1); coap_register_handler(r, COAP_REQUEST_GET, hnd_get_time); coap_register_handler(r, COAP_REQUEST_PUT, hnd_put_time); coap_register_handler(r, COAP_REQUEST_DELETE, hnd_delete_time); /* Document resource for .well-known/core request */ coap_add_attr(r, coap_make_str_const("ct"), coap_make_str_const("0"), 0); coap_add_attr(r, coap_make_str_const("title"), coap_make_str_const("\"Internal Clock\""), 0); coap_add_attr(r, coap_make_str_const("rt"), coap_make_str_const("\"secs\""), 0); coap_add_attr(r, coap_make_str_const("if"), coap_make_str_const("\"clock\""), 0); coap_add_resource(ctx, r); } ``` **Dynamic Resources Set Up** ``` #include /* Regular DELETE handler - used by resources created by the * Unknown Resource PUT handler */ void hnd_delete(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { /* .. code .. */ /* Dynamic resource no longer required - delete it */ coap_delete_resource(ctx, resource); } /* Regular GET handler - used by resources created by the * Unknown Resource PUT handler */ void hnd_get(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { coap_str_const_t *get_uri_path; coap_string_t *get_query; coap_opt_iterator_t opt_iter; coap_opt_filter_t filter; coap_opt_t *option; int len; /* * request will be NULL if an Observe triggered request, so the uri_path, * if needed, must be abstracted from the resource. * The uri_path string is a const pointer */ get_uri_path = coap_resource_get_uri_path(resource); get_query = query; /* .. code .. */ } /* Regular PUT handler - used by resources created by the * Unknown Resource PUT handler */ void hnd_put(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { coap_string_t *put_uri_path; /* get the uri_path */ put_uri_path = coap_get_uri_path(request); if (!put_uri_path) { response->code = COAP_RESPONSE_CODE(404); return; } /* .. code .. */ /* Need to do this as coap_get_uri_path() created it */ coap_delete_string(put_uri_path); } /* Unknown Resource PUT handler */ void hnd_unknown_put(coap_context_t *ctx, coap_resource_t *resource, coap_session_t *session, coap_pdu_t *request, coap_string_t *token, coap_string_t *query, coap_pdu_t *response) { coap_resource_t *r; int len; coap_string_t *uri_path; /* get the uri_path - which will get used by coap_resource_init() */ uri_path = coap_get_uri_path(request); if (!uri_path) { response->code = COAP_RESPONSE_CODE(404); return; } /* Check if new URI Path is valid */ if (!check_url_fn (uri_path, request->code)) { response->code = COAP_RESPONSE_CODE(404); coap_delete_string(uri_path); return; } /* * Create a resource to handle the new URI * uri_path will get deleted when the resource is removed */ r = coap_resource_init((coap_str_const_t*)uri_path, COAP_RESOURCE_FLAGS_RELEASE_URI | COAP_RESOURCE_FLAGS_NOTIFY_NON); coap_register_handler(r, COAP_REQUEST_PUT, hnd_put); coap_register_handler(r, COAP_REQUEST_DELETE, hnd_delete); /* We possibly want to Observe the GETs */ coap_resource_set_get_observable(r, 1); coap_register_handler(r, COAP_REQUEST_GET, hnd_get); coap_add_resource(ctx, r); /* Do the PUT for this first call */ hnd_put(ctx, r, session, request, token, query, response); return; } /* Initialize single Unknown Resource PUT handler */ static void init_resources(coap_context_t *ctx) { coap_resource_t *r; /* Create a resource to handle PUTs to unknown URIs */ r = coap_resource_unknown_init(hnd_unknown_put); /* * Additional handlers can be added - for example * coap_register_handler(r, COAP_REQUEST_POST, hnd_post_unknown); * coap_register_handler(r, COAP_REQUEST_GET, hnd_get_unknown); * coap_register_handler(r, COAP_REQUEST_DELETE, hnd_delete_unknown); */ coap_add_resource(ctx, r); } ``` ## SEE ALSO [**coap\_attribute**(3)](/coap_attribute/3.md), [**coap\_context**(3)](/coap_context/3.md), [**coap\_observe**(3)](/coap_observe/3.md) and [**coap\_handler**(3)](/coap_handler/3.md) ## FURTHER INFORMATION See "RFC7252: The Constrained Application Protocol (CoAP)" for further information. ## BUGS Please report bugs on the mailing list for libcoap: libcoap-developers@lists.sourceforge.net ## AUTHORS The libcoap project \