input_gadgets: gadgets_retrieve_weather_forecast() neu

1 files changed, 126 insertions, 0 deletions

diff --git a/input_gadgets.c b/input_gadgets.c
index f452ca0..0426c56 100644
--- a/input_gadgets.c
+++ b/input_gadgets.c
@@ -2,6 +2,11 @@
 #include <stdlib.h>
 #include <curl/curl.h>
 #include <regex.h>
+#include <stdio.h>
+#include <libxml/parser.h>
+#include <libxml/tree.h>
+#include <time.h>
+#include <math.h>
 
 #include "input_gadgets.h"
 
@@ -92,3 +97,124 @@ int gadgets_retrieve_current_temperature(unsigned char *output, int max_len)
   free(chunk.memory);
   return 0;
 }
+
+xmlNode *xml_find_node_by_name(xmlNode *cur_node, char *name)
+{
+  while (cur_node) {
+    if ((cur_node -> type == XML_ELEMENT_NODE) &&
+      (strcmp(cur_node -> name, name) == 0))
+      return cur_node;
+    cur_node = cur_node -> next;
+  }
+  return NULL;
+}
+
+int gadgets_retrieve_weather_forecast(unsigned char *output, int max_len)
+{
+  CURL *curl_handle;
+  CURLcode res;
+  struct MemoryStruct chunk;
+  int ret_val;
+
+  chunk.memory = malloc(1);
+  chunk.size = 0;
+
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  curl_handle = curl_easy_init();
+  if (!curl_handle) {
+    perror("Failed to init curl");
+    free(chunk.memory);
+    return EXIT_FAILURE;
+  }
+  curl_easy_setopt(curl_handle, CURLOPT_URL, "https://api.met.no/weatherapi/locationforecast/1.9/?lat=50.8830&lon=11.6223&msl=170");
+  curl_easy_setopt(curl_handle, CURLOPT_FOLLOWLOCATION, 1L);
+  curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
+  curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);
+  curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");
+  res = curl_easy_perform(curl_handle);
+  curl_easy_cleanup(curl_handle);
+  if (res != CURLE_OK) {
+    fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
+    free(chunk.memory);
+    return EXIT_FAILURE;
+  }
+
+  LIBXML_TEST_VERSION
+
+  xmlDocPtr doc;
+  doc = xmlReadMemory(chunk.memory, chunk.size, "noname.xml", NULL, 0);
+  free(chunk.memory);
+  if (doc == NULL) {
+    fprintf(stderr, "Failed to parse document\n");
+    return EXIT_FAILURE;
+  }
+
+  xmlNode *cur_node = NULL;
+  xmlNode *sub_node = NULL;
+  cur_node = xmlDocGetRootElement(doc);
+  if (!cur_node) {
+    fprintf(stderr, "Failed to reach root node of xml\n");
+    return EXIT_FAILURE;
+  }
+  cur_node = xml_find_node_by_name(cur_node, "weatherdata");
+  if (!cur_node) {
+    fprintf(stderr, "Failed to enter <weatherdata>\n");
+    return EXIT_FAILURE;
+  }
+  cur_node = xml_find_node_by_name(cur_node -> children, "product");
+  if (!cur_node) {
+    fprintf(stderr, "Failed to enter <product>\n");
+    return EXIT_FAILURE;
+  }
+
+  float rain_total = 0, temp_min = NAN, temp_max = NAN, wind_max = NAN, cur_val;
+
+  char time_str[2][21];
+  time_t now;
+  time(&now);
+  now = ((int)(now/60/60))*60*60;
+
+  for (cur_node = cur_node -> children; cur_node; cur_node = cur_node->next) {
+    if ((cur_node->type == XML_ELEMENT_NODE) && (strcmp(cur_node->name,"time")==0) && (strcmp(xmlGetProp(cur_node,"datatype"),"forecast")==0)) {
+      for (int i=0; i<=14; i++) {
+        now += i*60*60;
+        strftime(time_str[0],21,"%Y-%m-%dT%H:%M:%SZ",gmtime(&now));
+        now += 60*60;
+        strftime(time_str[1],21,"%Y-%m-%dT%H:%M:%SZ",gmtime(&now));
+        now -= (i+1)*60*60;
+        if ((strcmp(time_str[1],xmlGetProp(cur_node,"from"))==0) && (strcmp(time_str[1],xmlGetProp(cur_node,"to"))==0)) {
+          sub_node = xml_find_node_by_name(cur_node -> children,"location");
+          cur_val = atof(xmlGetProp(xml_find_node_by_name(sub_node -> children, "temperature"), "value"));
+          if (isnan(temp_max) || (cur_val > temp_max))
+            temp_max = cur_val;
+          if (isnan(temp_min) || (cur_val < temp_min))
+            temp_min = cur_val;
+          cur_val = atof(xmlGetProp(xml_find_node_by_name(sub_node -> children, "windSpeed"),"mps"));
+          if (isnan(wind_max) || (cur_val > wind_max))
+            wind_max = cur_val;
+        }
+        if ((strcmp(time_str[0],xmlGetProp(cur_node,"from"))==0) && (strcmp(time_str[1],xmlGetProp(cur_node,"to"))==0)) {
+          sub_node = xml_find_node_by_name(cur_node -> children,"location");
+          if (!sub_node)
+            continue;
+          sub_node = xml_find_node_by_name(sub_node -> children, "precipitation");
+          if (!sub_node)
+            continue;
+          rain_total += atof(xmlGetProp(sub_node,"value"));
+        }
+      }
+    }
+  }
+  xmlFreeDoc(doc);
+  xmlCleanupParser();
+
+  int i = snprintf(output, max_len, "%0.1f ,, %0.1f °C; %0.1f mm; %0.1f m/s;", temp_min, temp_max, rain_total, wind_max);
+  for (; i>=0; i--)
+    if (output[i] == '.')
+      output[i] = ',';
+    else if (output[i] == ',')
+      output[i] = '.';
+
+  return EXIT_SUCCESS;
+}