The migration from version 1 is not treated here because bindings version 1
are very old and probably does not exist anymore. If needed you can refer
-to the old [guide to migrate bindings from v1 to v2](afb-migration-v1-to-v2.md).
+to the old [guide to migrate bindings from v1 to v2](legacy/afb-migration-v1-to-v2.md).
Differences between version 2 and version 3
### in v3 all is api
-The version 3 introduce the concept of "API" that gather what was called before
+The version 3 introduces the concept of "API" that gather what was called before
the daemon and the service. This is the new concept that predates the 2 others.
The concept of API is intended to allow the definition of multiple APIs
Because there is potentially several "API", the functions that were without
context in bindings version 2 need now to tell what API is consumer.
-To be compatible with version 2, the bindings v3 still have a default hidden
+To be compatible with version 2, bindings v3 still have a default hidden
context: the default API named **afbBindingV3root**.
To summarize, the functions of class **daemon** and **service** use the default
This task list is:
1. Use the automatic migration procedure described below
-2. Adapt the init and preinit functions
-3. Consider to change to use the new reply
-4. Consider to change to use the new (sub)call
+2. Adapt the functions **preinit**, **init** and **onevent**
+3. Consider use of the new reply
+4. Consider use of the new (sub)call
+5. Consider use of event handlers
The remaining chapters explain these task with more details.
--------------------
A tiny **sed** script is intended to perform a first pass on the code that
-you want to upgrade. It can be down using **curl** and applied using **sed**
+you want to upgrade. It can be done using **curl** and applied using **sed**
as below.
```bash
sed -i -f $SED file1 file2 file3...
```
-This automatic action does most of the boring job nut not all the job.
+This automatic action does most of the boring job but not all the job.
The remaining of this guide explains the missing part.
-Adapt the init and preinit functions
-------------------------------------
+Adapt the functions preinit, init and onevent
+----------------------------------------------
-Consider to change to use the new reply
----------------------------------------
+The signature of the functions **preinit**, **init** and **onevent** changed
+to include the target api.
-Consider to change to use the new (sub)call
--------------------------------------------
+The functions of the v2:
+
+```C
+int (*preinit)();
+int (*init)();
+void (*onevent)(const char *event, struct json_object *object);
+```
+
+Gain a new first argument of type **afb_api_t** as below:
+
+```C
+int (*preinit)(afb_api_t api);
+int (*init)(afb_api_t api);
+void (*onevent)(afb_api_t api, const char *event, struct json_object *object);
+```
+
+For the migration, it is enough to just add the new argument without
+using it.
+
+Consider use of the new reply
+-----------------------------
+
+The v3 allows error reply with JSON object. To achieve it, an unified
+reply function's family is introduced:
+
+```C
+void afb_req_reply(afb_req_t req, json_object *obj, const char *error, const char *info);
+void afb_req_reply_v(afb_req_t req, json_object *obj, const char *error, const char *info, va_list args);
+void afb_req_reply_f(afb_req_t req, json_object *obj, const char *error, const char *info, ...);
+```
+
+The functions **success** and **fail** are still supported.
+These functions are now implemented as the following macros:
+
+
+```C
+#define afb_req_success(r,o,i) afb_req_reply(r,o,NULL,i)
+#define afb_req_success_f(r,o,...) afb_req_reply_f(r,o,NULL,__VA_ARGS__)
+#define afb_req_success_v(r,o,f,v) afb_req_reply_v(r,o,NULL,f,v)
+#define afb_req_fail(r,e,i) afb_req_reply(r,NULL,e,i)
+#define afb_req_fail_f(r,e,...) afb_req_reply_f(r,NULL,e,__VA_ARGS__)
+#define afb_req_fail_v(r,e,f,v) afb_req_reply_v(r,NULL,e,f,v)
+```
+
+This is a decision of the developer to switch to the new family
+**afb_req_reply** or to keep the good old functions **afb_req_fail**
+adn **afb_req_success**.
+
+Consider use of the new (sub)call
+---------------------------------
+
+The new call and subcall (the functions **afb_api_call**, **afb_api_call_sync**,
+**afb_req_subcall** and **afb_req_subcall_sync**) functions are redesigned
+to better fit the new reply behaviour. In most case the developer will benefit
+of the new behavior that directly gives result and error without enforcing
+to parse the JSON object result.
+
+The subcall functions are also fully redesigned to allow precise handling
+of the context and event subscriptions. The new design allows you to specify:
+
+ - whether the subcall is made in the session of the caller or in the session
+ of the service
+ - whether the credentials to use are those of the caller or those of the
+ service
+ - whether the caller or the service or both or none will receive the
+ eventually events during the subcall.
+
+See [calls](reference-v3/func-api/#calls-and-job-functions) and
+[subcalls](reference-v3/func-req/#subcall-functions).
+
+
+Consider use of event handlers
+------------------------------
+
+Binding V3 brings new ways of handling event in services. You can register
+functions that will handle specific events and that accept closure arguments.
+See [**afb_api_event_handler_add** and **afb_api_event_handler_del**](reference-v3/func-api/#event-functions)
Code Review / src / app-framework-binder.git / blobdiff