Simple streaming functionality

[matches/MCTX3420.git] / server / sensor.c

diff --git a/server/sensor.c b/server/sensor.c
index 83ffaaa..6222510 100644 (file)
--- a/server/sensor.c
+++ b/server/sensor.c
@@ -5,9 +5,8 @@
  */
 
 
-
+#include "common.h"
 #include "sensor.h"
-#include "log.h"
 #include <math.h>
 
 /**
@@ -64,9 +63,10 @@ void Sensor_Init(Sensor * s, int id)
        s->read_offset = 0;
        s->id = id;
 
-       #define FILENAMESIZE 4
+       #define FILENAMESIZE BUFSIZ
        char filename[FILENAMESIZE];
-       if (s->id >= pow(10, FILENAMESIZE))
+       //if (s->id >= pow(10, FILENAMESIZE))
+       if (false)
        {
                Fatal("Too many sensors! FILENAMESIZE is %d; increase it and recompile.", FILENAMESIZE);
        }
@@ -116,7 +116,7 @@ void * Sensor_Main(void * arg)
                        {
                                Fatal("Wrote %d data points and expected to write %d to \"%s\" - %s", amount_written, SENSOR_DATABUFSIZ, strerror(errno));
                        }
-                       Log(LOGDEBUG, "Wrote %d data points for sensor %d", amount_written, s->id);
+                       //Log(LOGDEBUG, "Wrote %d data points for sensor %d", amount_written, s->id);
                pthread_mutex_unlock(&(s->mutex));
                // End of critical section
 
@@ -126,4 +126,107 @@ void * Sensor_Main(void * arg)
        return NULL;
 }
 
+/**
+ * Fill buffer with most recent sensor data
+ * @param s - Sensor to use
+ * @param buffer - Buffer to fill
+ * @param bufsiz - Size of buffer to fill
+ * @returns The number of DataPoints actually read
+ */
+int Sensor_Query(Sensor * s, DataPoint * buffer, int bufsiz)
+{
+       int amount_read = 0;
+       //CRITICAL SECTION (Don't access file while sensor thread is writing to it!)
+       pthread_mutex_lock(&(s->mutex));
+               
+               fseek(s->file, -bufsiz*sizeof(DataPoint), SEEK_END);
+               amount_read = fread(buffer, sizeof(DataPoint), bufsiz, s->file);
+               //Log(LOGDEBUG, "Read %d data points", amount_read);            
+       pthread_mutex_unlock(&(s->mutex));
+       return amount_read;
+}
+
+/**
+ * Handle a request to the sensor module
+ * @param context - The context to work in
+ * @param params - Parameters passed
+ */
+void Sensor_Handler(FCGIContext *context, char * params)
+{
+       DataPoint buffer[SENSOR_QUERYBUFSIZ];
+       StatusCodes status = STATUS_OK;
+       const char * key; const char * value;
+
+       int sensor_id = SENSOR_NONE;
+
+       while ((params = FCGI_KeyPair(params, &key, &value)) != NULL)
+       {
+               Log(LOGDEBUG, "Got key=%s and value=%s", key, value);
+               if (strcmp(key, "id") == 0)
+               {
+                       char *end;
+                       if (sensor_id != SENSOR_NONE)
+                       {
+                               Log(LOGERR, "Only one sensor id should be specified");
+                               status = STATUS_ERROR;
+                               break;
+                       }
+                       if (*value == '\0')
+                       {
+                               Log(LOGERR, "No id specified.");
+                               status = STATUS_ERROR;
+                               break;
+                       }
+                       //TODO: Use human readable sensor identifier string for API?
+                       sensor_id = strtol(value, &end, 10);
+                       if (*end != '\0')
+                       {
+                               Log(LOGERR, "Sensor id not an integer; %s", value);
+                               status = STATUS_ERROR;
+                               break;
+                       }
+               }
+               else
+               {
+                       Log(LOGERR, "Unknown key \"%s\" (value = %s)", key, value);
+                       status = STATUS_ERROR;
+                       break;
+               }               
+       }
+
+       if (sensor_id == SENSOR_NONE)
+       {
+               Log(LOGERR, "No sensor id specified");
+               status = STATUS_ERROR;
+       }
+       else if (sensor_id >= NUMSENSORS || sensor_id < 0)
+       {
+               Log(LOGERR, "Invalid sensor id %d", sensor_id);
+               status = STATUS_ERROR;
+       }
 
+       if (status == STATUS_ERROR)
+       {
+               FCGI_RejectJSON(context);
+       }
+       else
+       {
+               FCGI_BeginJSON(context, status);        
+               FCGI_JSONPair(key, value); // should spit back sensor ID
+               //Log(LOGDEBUG, "Call Sensor_Query...");
+               int amount_read = Sensor_Query(&(g_sensors[sensor_id]), buffer, SENSOR_QUERYBUFSIZ);
+               //Log(LOGDEBUG, "Read %d DataPoints", amount_read);
+               //Log(LOGDEBUG, "Produce JSON response");
+               FCGI_JSONKey("data");
+               FCGI_JSONValue("[");
+               for (int i = 0; i < amount_read; ++i)
+               {
+                       FCGI_JSONValue("[%f, %f]", buffer[i].time, buffer[i].value);
+                       if (i+1 < amount_read)
+                               FCGI_JSONValue(",");
+               }
+               FCGI_JSONValue("]");
+               //Log(LOGDEBUG, "Done producing JSON response");
+               FCGI_EndJSON(); 
+       }
+}