Add request parsing helper, add TIMEVAL_* macros, move timestamps to identify module
[matches/MCTX3420.git] / server / fastcgi.c
index bddac21..8c6355a 100644 (file)
@@ -8,7 +8,7 @@
 
 #include <fcgi_stdio.h>
 #include <openssl/sha.h>
-#include <time.h>
+#include <stdarg.h>
 
 #include "common.h"
 #include "sensor.h"
@@ -31,13 +31,66 @@ struct FCGIContext {
 };
 
 /**
- * Identifies current version info. Useful for testing that the API is running.
- * TODO - Consider adding info about available sensors and actuators (eg capabilities)?
+ * Identifies build information and the current API version to the user.
+ * Also useful for testing that the API is running and identifying the 
+ * sensors and actuators present.
+ * @param context The context to work in
+ * @param params User specified paramters: [actuators, sensors]
  */ 
 static void IdentifyHandler(FCGIContext *context, char *params) {
+       bool ident_sensors = false, ident_actuators = false;
+       //const char *key, *value;
+       struct timeval now;
+       int i;
+
+       FCGIValue values[2] = {{"sensors", &ident_sensors, FCGI_BOOL_T},
+                                        {"actuators", &ident_actuators, FCGI_BOOL_T}};
+
+       if (!FCGI_ParseRequest(context, params, values, 2))
+               return;
+
+       /*while ((params = FCGI_KeyPair(params, &key, &value))) {
+               if (!strcmp(key, "sensors")) {
+                       ident_sensors = !ident_sensors;
+               } else if (!strcmp(key, "actuators")) {
+                       ident_actuators = !ident_actuators;
+               }
+       }*/
+
        FCGI_BeginJSON(context, STATUS_OK);
        FCGI_JSONPair("description", "MCTX3420 Server API (2013)");
        FCGI_JSONPair("build_date", __DATE__ " " __TIME__);
+       FCGI_JSONLong("api_version", API_VERSION);
+
+       //Time and running statistics
+       gettimeofday(&now, NULL);
+       FCGI_JSONDouble("start_time", TIMEVAL_TO_DOUBLE(g_options.start_time));
+       FCGI_JSONDouble("current_time", TIMEVAL_TO_DOUBLE(now));
+       FCGI_JSONDouble("running_time", TIMEVAL_DIFF(now, g_options.start_time));
+
+       //Sensor and actuator information
+       if (ident_sensors) {
+               FCGI_JSONKey("sensors");
+               FCGI_JSONValue("{\n\t\t");
+               for (i = 0; i < NUMSENSORS; i++) {
+                       if (i > 0) {
+                               FCGI_JSONValue(",\n\t\t");
+                       }
+                       FCGI_JSONValue("\"%d\" : \"%s\"", i, g_sensor_names[i]); 
+               }
+               FCGI_JSONValue("\n\t}");
+       }
+       if (ident_actuators) {
+               FCGI_JSONKey("actuators");
+               FCGI_JSONValue("{\n\t\t");
+               for (i = 0; i < NUMACTUATORS; i++) {
+                       if (i > 0) {
+                               FCGI_JSONValue(",\n\t\t");
+                       }
+                       FCGI_JSONValue("\"%d\" : \"%s\"", i, g_actuator_names[i]); 
+               }
+               FCGI_JSONValue("\n\t}");
+       }
        FCGI_EndJSON();
 }
 
@@ -152,6 +205,87 @@ char *FCGI_KeyPair(char *in, const char **key, const char **value)
        return ptr;
 }
 
+/**
+ * Aids in parsing request parameters. Expected keys along with their type
+ * and whether or not they're required are provided. This function will then
+ * parse the parameter string to find these keys.
+ * @param context The context to work in
+ * @param params The parameter string to be parsed
+ * @param values An array of FCGIValue's that specify expected keys
+ * @param count The number of elements in 'values'.
+ * @return true If the parameter string was parsed successfully, false otherwise.
+ *         Modes of failure include: Invalid a parsing error on the value,
+ *                                   an unknown key is specified,
+ *                                   a key/value pair is specified more than once, or
+ *                                   not all required keys were present.
+ *         If this function returns false, it is guaranteed that FCGI_RejectJSON
+ *         has already been called with the appropriate description message.
+ */
+bool FCGI_ParseRequest(FCGIContext *context, char *params, FCGIValue values[], size_t count)
+{
+       const char *key, *value;
+       char buf[BUFSIZ], *ptr;
+       size_t i;
+       
+       while ((params = FCGI_KeyPair(params, &key, &value))) {
+               for (i = 0; i < count; i++) {
+                       if (!strcmp(key, values[i].key)) {
+                               FCGIValue *val = &values[i];
+
+                               if (FCGI_RECEIVED(val->flags)) {
+                                       snprintf(buf, BUFSIZ, "Value already specified for '%s'.", key);
+                                       FCGI_RejectJSON(context, buf);
+                                       return false;
+                               }
+                               val->flags |= FCGI_PARAM_RECEIVED;
+
+                               switch(FCGI_TYPE(val->flags)) {
+                                       case FCGI_BOOL_T:
+                                               *((bool*) val->value) = true;
+                                               break;
+                                       case FCGI_LONG_T:
+                                               *((long*) val->value) = strtol(value, &ptr, 10);
+                                               if (!*value || *ptr) {
+                                                       snprintf(buf, BUFSIZ, "Expected int for '%s' but got '%s'", key, value);
+                                                       FCGI_RejectJSON(context, FCGI_EscapeJSON(buf));
+                                                       return false;
+                                               }
+                                               break;
+                                       case FCGI_DOUBLE_T:
+                                               *((double*) val->value) = strtod(value, &ptr);
+                                               if (!*value || *ptr) {
+                                                       snprintf(buf, BUFSIZ, "Expected float for '%s' but got '%s'", key, value);
+                                                       FCGI_RejectJSON(context, FCGI_EscapeJSON(buf));
+                                                       return false;
+                                               }
+                                               break;
+                                       case FCGI_STRING_T:
+                                               *((const char**) val->value) = value;
+                                               break;
+                                       default:
+                                               Fatal("Invalid type %d given", FCGI_TYPE(val->flags));
+                               }
+                               break; //No need to search any more
+                       }
+               } //End for loop
+               if (i == count) {
+                       snprintf(buf, BUFSIZ, "Unknown key '%s' specified", key);
+                       FCGI_RejectJSON(context, FCGI_EscapeJSON(buf));
+                       return false;
+               }
+       }
+
+       //Check that required parameters are received
+       for (i = 0; i < count; i++) {
+               if (FCGI_IS_REQUIRED(values[i].flags) && !FCGI_RECEIVED(values[i].flags)) {
+                       snprintf(buf, BUFSIZ, "Key '%s' required, but was not given.", values[i].key);
+                       FCGI_RejectJSON(context, buf);
+                       return false;
+               }
+       }
+       return true;
+}
+
 /**
  * Begins a response to the client in JSON format.
  * @param context The context to work in.
@@ -163,21 +297,11 @@ void FCGI_BeginJSON(FCGIContext *context, StatusCodes status_code)
        printf("{\r\n");
        printf("\t\"module\" : \"%s\"", context->current_module);
        FCGI_JSONLong("status", status_code);
-
-       // Jeremy: Should we include a timestamp in the JSON; something like this?
-       double start_time = g_options.start_time.tv_sec + 1e-6*(g_options.start_time.tv_usec);
-       struct timeval now;
-       gettimeofday(&now, NULL);
-       double current_time = now.tv_sec + 1e-6*(now.tv_usec);
-       FCGI_JSONDouble("start_time", start_time);
-       FCGI_JSONDouble("current_time", current_time);
-       FCGI_JSONDouble("running_time", current_time - start_time);
-       
 }
 
 /**
  * Adds a key/value pair to a JSON response. The response must have already
- * been initiated by FCGI_BeginJSON. Note that characters are not escaped.
+ * been initiated by FCGI_BeginJSON. Special characters are not escaped.
  * @param key The key of the JSON entry
  * @param value The value associated with the key.
  */
@@ -235,13 +359,33 @@ void FCGI_EndJSON()
 }
 
 /**
- * To be used when the input parameters are invalid. The return data will
- * have a status of STATUS_ERROR, along with other debugging information.
- * @param context The context to work in
+ * Escapes a string so it can be used as a JSON string value.
+ * Does not support unicode specifiers in the form of \uXXXX.
+ * @param buf The string to be escaped
+ * @return The escaped string (return value == buf)
  */
-void FCGI_RejectJSON(FCGIContext *context)
+char *FCGI_EscapeJSON(char *buf)
 {
-       FCGI_RejectJSONEx(context, STATUS_ERROR, "Invalid request");
+       int length, i;
+       length = strlen(buf);
+       
+       //Escape special characters. Must count down to escape properly
+       for (i = length - 1; i >= 0; i--) {
+               if (buf[i] < 0x20) { //Control characters
+                       buf[i] = ' ';
+               } else if (buf[i] == '"') {
+                       if (i-1 >= 0 && buf[i-1] == '\\') 
+                               i--;
+                       else
+                               buf[i] = '\'';
+               } else if (buf[i] == '\\') {
+                       if (i-1 >= 0 && buf[i-1] == '\'')
+                               i--;
+                       else
+                               buf[i] = ' ';
+               }
+       }
+       return buf;
 }
 
 /**
@@ -319,8 +463,12 @@ void * FCGI_RequestLoop (void *data)
                size_t lastchar = strlen(module) - 1;
                if (lastchar > 0 && module[lastchar] == '/')
                        module[lastchar] = 0;
+
+               //Default to the 'identify' module if none specified
+               if (!*module) 
+                       strcpy(module, "identify");
                
-               if (!*module || !strcmp("identify", module)) {
+               if (!strcmp("identify", module)) {
                        module_handler = IdentifyHandler;
                } else if (!strcmp("control", module)) {
                        module_handler = Control_Handler;
@@ -332,8 +480,7 @@ void * FCGI_RequestLoop (void *data)
                if (module_handler) {
                        module_handler(&context, params);
                } else {
-                       strncat(module, " (unhandled)", BUFSIZ);
-                       FCGI_RejectJSON(&context);
+                       FCGI_RejectJSON(&context, "Unhandled module");
                }
                context.response_number++;
 

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