Reduce busy-waiting during Celestrak query.

Author: mdkendall

src/predictor.cpp

@@ -24,6 +24,8 @@
 #include <string.h>
 #include <time.h>
 
+#define TM_HTTP_BODY_WAIT   250
+
 Predictor::Predictor(void) {
 }
 
@@ -46,32 +48,36 @@ bool Predictor::init(uint32_t catNum) {
     http.begin(url);
     http.setFollowRedirects(HTTPC_STRICT_FOLLOW_REDIRECTS);
     if ((retCode = http.GET()) == HTTP_CODE_OK) {
+
+        delay(TM_HTTP_BODY_WAIT);
         WiFiClient response = http.getStream();
         satName = response.readStringUntil('\n');
-        tle[0] = response.readStringUntil('\n');
-        tle[1] = response.readStringUntil('\n');
-
-        // Check that the response looks plausible
-        if (satName.length() && !satName.startsWith("No GP data") && tle[0].length() && tle[1].length()) {
-
-            // Convert the string format TLE to SGP4 elements and initialise the satellite record.
-            // twoline2rv needs non-const char arrays (it may modify them), so we make temporary copies.
-            strncpy(tleTemp[0], tle[0].c_str(), 80);
-            strncpy(tleTemp[1], tle[1].c_str(), 80);
-            SGP4Funcs::twoline2rv(tleTemp[0], tleTemp[1], 'a', wgs72, satrec);
-
-            // Convert the TLE epoch to a standard UNIX timestamp
-            SGP4Funcs::invjday_SGP4(satrec.jdsatepoch, satrec.jdsatepochF, year, mon, day, hr, minute, sec);
-            t.tm_year = year - 1900; t.tm_mon = mon - 1; t.tm_mday = day; t.tm_hour = hr; t.tm_min = minute; t.tm_sec = sec;
-            epoch = mktime(&t);
-            done = true;
-
-            // Debug
-            Serial.println(String("Predictor init complete:"));
-            Serial.println(String("  Sat Name: ") + satName);
-            Serial.println(String("  TLE[0]: ") + tle[0]);
-            Serial.println(String("  TLE[1]: ") + tle[1]);
-            Serial.println(String("  Epoch: ") + String(epoch));
+        if (satName.length() && !satName.startsWith("No GP data")) {
+
+            tle[0] = response.readStringUntil('\n');
+            tle[1] = response.readStringUntil('\n');
+
+            if (tle[0].length() && tle[1].length()) {
+
+                // Convert the string format TLE to SGP4 elements and initialise the satellite record.
+                // twoline2rv needs non-const char arrays (it may modify them), so we make temporary copies.
+                strncpy(tleTemp[0], tle[0].c_str(), 80);
+                strncpy(tleTemp[1], tle[1].c_str(), 80);
+                SGP4Funcs::twoline2rv(tleTemp[0], tleTemp[1], 'a', wgs72, satrec);
+
+                // Convert the TLE epoch to a standard UNIX timestamp
+                SGP4Funcs::invjday_SGP4(satrec.jdsatepoch, satrec.jdsatepochF, year, mon, day, hr, minute, sec);
+                t.tm_year = year - 1900; t.tm_mon = mon - 1; t.tm_mday = day; t.tm_hour = hr; t.tm_min = minute; t.tm_sec = sec;
+                epoch = mktime(&t);
+                done = true;
+
+                // Debug
+                Serial.println(String("Predictor init complete:"));
+                Serial.println(String("  Sat Name: ") + satName);
+                Serial.println(String("  TLE[0]: ") + tle[0]);
+                Serial.println(String("  TLE[1]: ") + tle[1]);
+                Serial.println(String("  Epoch: ") + String(epoch));
+            }
         }
     } else {
         Serial.printf("Predictor init failed with HTTP %d\n", retCode);