Working on charts

git-svn-id: file:///home/jan/tmp/wetterstation/trunk@77 dd492736-c11a-0410-ad51-8c26713eaf7f

cronjob/chart/definitions.h

@@ -37,6 +37,8 @@
 #define  ERROR_SEIINST "Signal-Fehler: Kann Signalhandler zum beenden nicht installieren\n"
 #define  ERROR_FORK    "Fork-Fehler: Kann keinen neuen Prozess anlegen\n"
 #define  ERROR_STAT    "Kann Stat nicht ausführen\n"
+#define  ERROR_MAKECONN "PgSQL-Fehler: Kann Datenbankverbindung nicht herstellen\n"
+#define  ERROR_QUERY	"PgSQL-Fehler: Kann query nicht sudführen \n"
 
 
 /* Puffergrößen -------------------------------------------------------- */

cronjob/chart/image_file/image_data.c

@@ -0,0 +1,96 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+#include <postgresql/libpq-fe.h>
+#include "image_data.h"
+#include "image_common.h"
+#include "../common.h"
+#include "../definitions.h"
+
+#define BUFFSIZE 512
+#define BUFFSIZE_EXTRA 2048
+
+
+typedef struct pix_list *pix_list_ptr;
+typedef struct pix_list {
+  pix_list_ptr 	next;
+  int 		x_pix_coord;
+  int 		value_count;
+  int 		value_sum;
+} pix_list_t;
+
+
+
+static char *get_conn_string();
+static PGconn *pg_check_connect(char *);
+static PGresult *pg_check_exec(PGconn *, char *);
+static char *get_type_table_by_id(PGconn *, int );
+
+
+
+
+
+
+pix_list_ptr get_pix_list(int c_width){
+  double seconds_per_pix = (img_cfg.show_interval * 0.1)/(c_width * 0.1);
+  PGconn *connection = pg_check_connect(get_conn_string());
+
+}
+
+/* baut den String fuer die Postgres-Verbindung zusammen */
+static char *get_conn_string(){
+    char *conn_string = malloc(sizeof(char)*BUFFSIZE);
+    snprintf(conn_string, BUFFSIZE, "host=%s dbname=%s user=%s password=%s connect_timeout=%s", global_opts.pg_host, global_opts.pg_database, global_opts.pg_user, global_opts.pg_pass, global_opts.pg_timeout);
+    return conn_string;
+}
+
+
+/* Baut eine Vebindung zur postgres auf, bricht mit fehler ab wenn nicht moeglich */
+static PGconn *pg_check_connect(char *conn_string){
+  PGconn *conn = PQconnectdb(conn_string);			/* Connection aufbauen */
+  if(PQstatus(conn) != CONNECTION_OK){
+    DEBUGOUT2("\nFehler beim Aufbau der Datenbankverbindung\n%s\n", PQerrorMessage(conn));
+    exit_error(ERROR_MAKECONN);
+  }
+  DEBUGOUT1("Verbindung hergestellt \n");
+  return conn;
+}
+
+/* Fuehrt ein SQL-Statement aus. Bricht mit fehler ab wenn nicht moeglich */
+static PGresult *pg_check_exec(PGconn *conn, char *query){
+  PGresult *res;
+  res = PQexec(conn, query);
+  if(!res || PQresultStatus(res) != PGRES_TUPLES_OK){
+    DEBUGOUT2("Fehler beim exec: %s\n", query);
+    exit_error(ERROR_QUERY);
+  } else {
+    DEBUGOUT2("Query: '%s' ausgeführt\n", query);
+  }
+  return res;
+}
+
+
+/* Tabellenname des typs aus der Datenbank holen */
+static char *get_type_table_by_id(PGconn *connection, int sens_id){
+  char *table;
+  int table_field;
+  PGresult *table_res;
+  char *query_buff 	= malloc(sizeof(char)*BUFFSIZE);
+
+  snprintf(query_buff, BUFFSIZE, "select typen.tabelle as tbl FROM typen, sensoren WHERE sensoren.id=%d AND typen.typ=sensoren.typ", sens_id);
+  table_res = pg_check_exec(connection, query_buff);
+  
+  if(PQntuples(table_res) < 1)
+    return NULL;
+  
+  table_field = PQfnumber(table_res, "tbl");
+  table       = strdup(PQgetvalue(table_res, 0, table_field));
+  
+  DEBUGOUT2("\tTabelle: %s \n", table);
+
+  PQclear(table_res);
+  free(query_buff);
+
+  return table;
+}