Refactor GENERIC_RESOURCE macro

Now callback functions get the URI of the request, this allows to use a
single resource for multiple different URIs.
The is_json flag is now gone for the to-string function, instead the
macro has an is_str flag. If set this automagically produces quotes
around the string for json output.
Now from-string functions can return an error-code, 0 for success, -1
for error.

apps/json-resource/generic_resource.c

@@ -105,6 +105,20 @@ json_parse_variable
   return 0;
 }
 
+static const char *get_uri (void *request)
+{
+  static char buf [MAX_URI_STRING_LENGTH];
+  const char *uri;
+  size_t len = coap_get_header_uri_path (request, &uri);
+  if (len > sizeof (buf) - 1) {
+    *buf = '\0';
+  } else {
+    strncpy (buf, uri, len);
+    buf [len] = '\0';
+  }
+  return buf;
+}
+
 void generic_get_handler
   ( void *request
   , void *response
@@ -112,13 +126,15 @@ void generic_get_handler
   , uint16_t preferred_size
   , int32_t *offset
   , char *name
-  , size_t (*to_str)(const char *name, uint8_t is_json, char *buf, size_t bsize)
+  , int is_str
+  , size_t (*to_str)(const char *name, const char *uri, char *buf, size_t bsize)
   )
 {
   int success = 1;
-  char temp [100];
+  char temp [MAX_GET_STRING_LENGTH];
   size_t len = 0;
   unsigned int accept = -1;
+  const char *uri = get_uri (request);
 
   REST.get_header_accept (request, &accept);
   if (  accept != -1
@@ -127,30 +143,40 @@ void generic_get_handler
      )
   {
     success = 0;
-    REST.set_response_status(response, REST.status.NOT_ACCEPTABLE);
+    REST.set_response_status (response, REST.status.NOT_ACCEPTABLE);
     return;
   }
 
   // TEXT format
   if (accept == REST.type.APPLICATION_JSON) {
     len += snprintf
-      (temp + len, sizeof (temp) - len, "{\n \"%s\" : ", name);
+      ( temp + len
+      , sizeof (temp) - len
+      , "{\n \"%s\" : %s"
+      , name
+      , is_str ? "\"" : ""
+      );
     if (len > sizeof (temp)) {
       success = 0;
       goto out;
     }
-    len += to_str (name, 1, temp + len, sizeof (temp) - len);
+    len += to_str (name, uri, temp + len, sizeof (temp) - len);
     if (len > sizeof (temp)) {
       success = 0;
       goto out;
     }
-    len += snprintf (temp + len, sizeof (temp) - len, "\n}\n");
+    len += snprintf 
+      ( temp + len
+      , sizeof (temp) - len
+      , "%s\n}\n"
+      , is_str ? "\"" : ""
+      );
     if (len > sizeof (temp)) {
       success = 0;
       goto out;
     }
   } else { // TEXT Format
-    len += to_str (name, 0, temp + len, sizeof (temp) - len);
+    len += to_str (name, uri, temp + len, sizeof (temp) - len);
     if (len > sizeof (temp)) {
       success = 0;
       goto out;
@@ -166,7 +192,7 @@ void generic_get_handler
   REST.set_response_payload (response, buffer, len);
 out :
   if (!success) {
-    REST.set_response_status(response, REST.status.BAD_REQUEST);
+    REST.set_response_status (response, REST.status.BAD_REQUEST);
   }
 }
 
@@ -177,7 +203,7 @@ void generic_put_handler
   , uint16_t preferred_size
   , int32_t *offset
   , char *name
-  , void (*from_str)(const char *name, const char *s)
+  , int (*from_str)(const char *name, const char *uri, const char *s)
   )
 {
   int success = 1;
@@ -185,9 +211,10 @@ void generic_put_handler
   size_t len = 0;
   const uint8_t  *bytes  = NULL;
   uint16_t c_ctype;
+  const char *uri = get_uri (request);
   REST.get_header_content_type (request, &c_ctype);
 
-  if (from_str && (len = coap_get_payload(request, &bytes))) {
+  if (from_str && (len = coap_get_payload (request, &bytes))) {
     if (c_ctype == REST.type.TEXT_PLAIN) {
       int l = MIN (len, sizeof (temp) - 1);
       temp [sizeof (temp) - 1] = 0;
@@ -199,14 +226,17 @@ void generic_put_handler
         goto out;
       }
     }
-    from_str (name, temp);
+    if (from_str (name, uri, temp) < 0) {
-    REST.set_response_status(response, REST.status.CHANGED);
+      success = 0;
+    } else {
+      REST.set_response_status (response, REST.status.CHANGED);
+    }
   } else {
     success = 0;
   }
 out:
   if (!success) {
-    REST.set_response_status(response, REST.status.BAD_REQUEST);
+    REST.set_response_status (response, REST.status.BAD_REQUEST);
   }
 }
 

apps/json-resource/generic_resource.h

@@ -50,6 +50,9 @@
 #define STR__(s) #s
 #define STR_(s) STR__(s)
 
+#define MAX_GET_STRING_LENGTH 100
+#define MAX_URI_STRING_LENGTH  30
+
 /*
  * A macro that extends the resource definition and also sets up the
  * necessary handler function that calls format/parse routines that
@@ -60,7 +63,7 @@
  * Yes, this *is* a hack. But I hate boilerplate code.
  */
 
-#define GENERIC_RESOURCE(name, title, unit, fs, ts)                        \
+#define GENERIC_RESOURCE(name, title, unit, is_str, fs, ts)                \
   static void name##_get_handler                                           \
     ( void *request                                                        \
     , void *response                                                       \
@@ -70,7 +73,7 @@
     )                                                                      \
   {                                                                        \
     generic_get_handler                                                    \
-      (request, response, buffer, ps, offset, STR_(name), ts);             \
+      (request, response, buffer, ps, offset, STR_(name), is_str, ts);     \
   }                                                                        \
   static void name##_put_handler                                           \
     ( void *request                                                        \
@@ -134,7 +137,8 @@ extern void generic_get_handler
   , uint16_t preferred_size
   , int32_t *offset
   , char *name
-  , size_t (*to_str)(const char *name, uint8_t is_json, char *buf, size_t bsize)
+  , int is_str
+  , size_t (*to_str)(const char *name, const char *uri, char *buf, size_t bsize)
   );
 
 /**
@@ -157,7 +161,7 @@ extern void generic_put_handler
   , uint16_t preferred_size
   , int32_t *offset
   , char *name
-  , void (*from_str)(const char *name, const char *s)
+  , int (*from_str)(const char *name, const char *uri, const char *s)
   );
 
 /*

apps/time/resource_gmtime.c

@@ -17,7 +17,7 @@
 #include "er-coap.h"
 #include "generic_resource.h"
 
-size_t time_to_string (const char *name, uint8_t is_json, char *buf, size_t bs)
+size_t time_to_string (const char *name, const char *uri, char *buf, size_t bs)
 {
     struct timeval tv;
     struct tm tm;
@@ -30,12 +30,10 @@ size_t time_to_string (const char *name, uint8_t is_json, char *buf, size_t bs)
     return snprintf
       ( buf
       , bs
-      , "%s%lu-%02u-%02u %02u:%02u:%02u %s%s"
+      , "%lu-%02u-%02u %02u:%02u:%02u %s"
-      , is_json ? "\"" : ""
       , 1900 + tm.tm_year
       , tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec
       , tm.tm_zone
-      , is_json ? "\"" : ""
       );
 }
 
@@ -43,6 +41,7 @@ GENERIC_RESOURCE \
     ( localtime
     , Local time
     , formatted time
+    , 1
     , NULL
     , time_to_string
     );
@@ -51,6 +50,7 @@ GENERIC_RESOURCE \
     ( utc
     , UTC
     , formatted time
+    , 1
     , NULL
     , time_to_string
     );

apps/time/resource_timestamp.c

@@ -21,32 +21,30 @@
 #include "er-coap.h"
 #include "generic_resource.h"
 
-void timestamp_from_string (const char *name, const char *s)
+int timestamp_from_string (const char *name, const char *uri, const char *s)
 {
   struct timeval tv;
   // FIXME: Platform has no strtoll (long long)?
   tv.tv_sec = strtol (s, NULL, 10);
   settimeofday (&tv, NULL);
+  return 0;
 }
 
 size_t
-timestamp_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+timestamp_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
   struct timeval tv;
-  char *fmt = "%ld";
-  if (is_json) {
-    fmt = "\"%ld\"";
-  }
   gettimeofday (&tv, NULL);
   // FIXME: Platform doesn't seem to support long long printing
   // We get empty string
-  return snprintf (buf, bsize, fmt, (long)tv.tv_sec);
+  return snprintf (buf, bsize, "%ld", (long)tv.tv_sec);
 }
 
 GENERIC_RESOURCE
   ( timestamp
   , Time
   , s
+  , 1
   , timestamp_from_string
   , timestamp_to_string
   );

apps/time/resource_timezone.c

@@ -17,13 +17,14 @@
 #include "er-coap.h"
 #include "generic_resource.h"
 
-void timezone_from_string (const char *name, const char *s)
+int timezone_from_string (const char *name, const char *uri, const char *s)
 {
   set_tz (s);
+  return 0;
 }
 
 size_t
-timezone_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+timezone_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
   if (get_tz (buf, bsize) == NULL) {
     *buf = '\0';
@@ -35,6 +36,7 @@ GENERIC_RESOURCE
   ( timezone
   , TZ
   , s
+  , 1
   , timezone_from_string
   , timezone_to_string
   );

examples/osd/arduino-ledstrip/sketch.pde

@@ -46,27 +46,25 @@ static uint8_t name_to_offset (const char * name)
 }
 
 static size_t
-color_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+color_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
-  char *fmt = "%d";
+  return snprintf (buf, bsize, "%d", color_rgb [name_to_offset (name)]);
-  if (is_json) {
-    fmt = "\"%d\"";
-  }
-  return snprintf (buf, bsize, fmt, color_rgb [name_to_offset (name)]);
 }
 
-void color_from_string (const char *name, const char *s)
+int color_from_string (const char *name, const char *uri, const char *s)
 {
     color_rgb [name_to_offset (name)] = atoi (s);
     Driver.begin();
     Driver.SetColor(color_rgb [0], color_rgb [1], color_rgb [2]);
     Driver.end();
+    return 0;
 }
 
 GENERIC_RESOURCE
   ( red
   , RED_LED
   , s
+  , 1
   , color_from_string
   , color_to_string
   );
@@ -75,6 +73,7 @@ GENERIC_RESOURCE
   ( green
   , GREEN_LED
   , s
+  , 1
   , color_from_string
   , color_to_string
   );
@@ -83,6 +82,7 @@ GENERIC_RESOURCE
   ( blue
   , BLUE_LED
   , s
+  , 1
   , color_from_string
   , color_to_string
   );
@@ -136,4 +136,3 @@ void loop (void)
 	}
 */
 }
-

examples/osd/arduino-sketch/resource_led_pwm.c

@@ -17,17 +17,18 @@
 #include "generic_resource.h"
 #include "led_pwm.h"
 
-void pwm_from_string (const char *name, const char *s)
+int pwm_from_string (const char *name, const char *uri, const char *s)
 {
     uint32_t tmp = strtoul (s, NULL, 10);
     if (tmp > 255) {
       tmp = 255;
     }
     pwm = tmp;
+    return 0;
 }
 
 size_t
-pwm_to_string (const char *name, uint8_t is_json, char *buf, size_t bufsize)
+pwm_to_string (const char *name, const char *uri, char *buf, size_t bufsize)
 {
   return snprintf (buf, bufsize, "%d", pwm);
 }
@@ -36,11 +37,12 @@ GENERIC_RESOURCE \
     ( led_pwm
     , LED PWM
     , duty-cycle
+    , 0
     , pwm_from_string
     , pwm_to_string
     );
 
-void period_from_string (const char *name, const char *s)
+int period_from_string (const char *name, const char *uri, const char *s)
 {
     uint32_t tmp = (strtoul (s, NULL, 10) + 50) / 100;
     if (tmp > 10) {
@@ -50,10 +52,11 @@ void period_from_string (const char *name, const char *s)
         tmp = 1;
     }
     period_100ms = tmp;
+    return 0;
 }
 
 size_t
-period_to_string (const char *name, uint8_t is_json, char *buf, size_t bufsize)
+period_to_string (const char *name, const char *uri, char *buf, size_t bufsize)
 {
   return snprintf (buf, bufsize, "%d", period_100ms * 100);
 }
@@ -62,12 +65,13 @@ GENERIC_RESOURCE \
     ( led_period
     , LED Period
     , ms
+    , 0
     , period_from_string
     , period_to_string
     );
 
 size_t
-analog2_v (const char *name, uint8_t is_json, char *buf, size_t bufsize)
+analog2_v (const char *name, const char *uri, char *buf, size_t bufsize)
 {
   return snprintf
     (buf, bufsize, "%d.%03d", analog2_voltage / 1000, analog2_voltage % 1000);
@@ -77,12 +81,13 @@ GENERIC_RESOURCE \
     ( analog2_voltage
     , Analog 2 voltage
     , V
+    , 0
     , NULL
     , analog2_v
     );
 
 size_t
-analog5_v (const char *name, uint8_t is_json, char *buf, size_t bufsize)
+analog5_v (const char *name, const char *uri, char *buf, size_t bufsize)
 {
   return snprintf
     (buf, bufsize, "%d.%03d", analog5_voltage / 1000, analog5_voltage % 1000);
@@ -92,6 +97,7 @@ GENERIC_RESOURCE \
     ( analog5_voltage
     , Analog 5 voltage
     , V
+    , 0
     , NULL
     , analog5_v
     );

examples/osd/led-strip/led-strip.c

@@ -77,16 +77,12 @@ static uint8_t name_to_offset (const char * name)
 }
 
 static size_t
-color_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+color_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
-  char *fmt = "%d";
+  return snprintf (buf, bsize, "%d", color_rgb [name_to_offset (name)]);
-  if (is_json) {
-    fmt = "\"%d\"";
-  }
-  return snprintf (buf, bsize, fmt, color_rgb [name_to_offset (name)]);
 }
 
-void color_from_string (const char *name, const char *s)
+int color_from_string (const char *name, const char *uri, const char *s)
 {
   color_rgb [name_to_offset (name)] = atoi (s);
   led_strip_begin ();
@@ -95,12 +91,14 @@ void color_from_string (const char *name, const char *s)
   printf ("Set to R:%d G:%d B:%d\n"
          , color_rgb [0], color_rgb [1], color_rgb [2])
          ;
+  return 0;
 }
 
 GENERIC_RESOURCE
   ( red
   , RED_LED
   , s
+  , 1
   , color_from_string
   , color_to_string
   );
@@ -109,6 +107,7 @@ GENERIC_RESOURCE
   ( green
   , GREEN_LED
   , s
+  , 1
   , color_from_string
   , color_to_string
   );
@@ -117,6 +116,7 @@ GENERIC_RESOURCE
   ( blue
   , BLUE_LED
   , s
+  , 1
   , color_from_string
   , color_to_string
   );

examples/osd/poti/poti.c

@@ -77,74 +77,73 @@ char         server_resource [20] = "led/G";
 int          interval = 10; /* Retransmit interval after no change in value */
 
 static size_t
-ip_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+ip_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
     #define IP(x) UIP_NTOHS(server_ipaddr.u16[x])
-    char *q = "\"";
-    if (!is_json) {
-        q = "";
-    }
     return snprintf
-        ( buf, bsize, "%s%x:%x:%x:%x:%x:%x:%x:%x%s"
+        ( buf, bsize, "%x:%x:%x:%x:%x:%x:%x:%x"
-        , q, IP(0), IP(1), IP(2), IP(3), IP(4), IP(5), IP(6), IP(7), q
+        , IP(0), IP(1), IP(2), IP(3), IP(4), IP(5), IP(6), IP(7)
         );
 }
 
-void ip_from_string (const char *name, const char *s)
+int ip_from_string (const char *name, const char *uri, const char *s)
 {
     /* Returns 1 if successful, only copy valid address */
     if (uiplib_ip6addrconv (s, &tmp_addr)) {
         uip_ip6addr_copy (&server_ipaddr, &tmp_addr);
+        return 0;
     }
+    return -1;
 }
 
 GENERIC_RESOURCE
   ( server_ip
   , ip
   , ipv6_address
+  , 1
   , ip_from_string
   , ip_to_string
   );
 
 static size_t
-resource_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+resource_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
-    char *q = "\"";
+    return snprintf (buf, bsize, "%s", server_resource);
-    if (!is_json) {
-        q = "";
-    }
-    return snprintf (buf, bsize, "%s%s%s", q, server_resource, q);
 }
 
-void resource_from_string (const char *name, const char *s)
+int resource_from_string (const char *name, const char *uri, const char *s)
 {
     strncpy (server_resource, s, sizeof (server_resource));
     server_resource [sizeof (server_resource) - 1] = 0;
+    return 0;
 }
 
 GENERIC_RESOURCE
   ( server_resource
   , led-resource
   , resource-name
+  , 1
   , resource_from_string
   , resource_to_string
   );
 
 static size_t
-interval_to_string (const char *name, uint8_t is_json, char *buf, size_t bsize)
+interval_to_string (const char *name, const char *uri, char *buf, size_t bsize)
 {
     return snprintf (buf, bsize, "%d", interval);
 }
 
-void interval_from_string (const char *name, const char *s)
+int interval_from_string (const char *name, const char *uri, const char *s)
 {
     interval = atoi (s);
+    return 0;
 }
 
 GENERIC_RESOURCE
   ( interval
   , interval
   , s
+  , 0
   , interval_from_string
   , interval_to_string
   );