YUN: Errors executing Curl or Client.get via Bridge: different behaviors based on length of commands/URL

From @roger77 on March 11, 2014 20:19

I got some strange behavior out of executing curl commands via Arduino to send data via json GET requests. I was also able to replicate the exact problem just by invoking the Client.get() function on a ever increasing URL. In particular if the total URL length is less than 300 the request executes correctly. Strangely enough, it also execute correctly if the URL length is greater than 500 and less than 800 characters. All URL longer than ~800 will just fails to be executed. Another odd behavior happens when the URL length is between 300 and 500 characters: the request will succeed but its execution time will always take more than 10 sec (see table below). This behavior happens either if I send request to my own server or if I direct the request to echo.jsontest.com.

I simplified the code and it seems length of URL is part of the problem. I tried to follow the forum suggestion and added the '-u' to the python call but it didn't affect the problem.

Here's the link to the forum post and I hope this is a better place to report what I think is a bug: http://forum.arduino.cc/index.php?topic=222569.msg1626070#msg1626070

Here's the full output: first column is the URL length, second is execution time in ms, last column is amount of free memory in bytes. Execution times greater than 400ms and less than 3 sec usually indicate a successful Client.get() execution. When the execution time is less than 200ms the Client.get() failed to reach the server. I reported only the table up to 1000 chars of command. The program will continue with failed Client.get() until it runs out of memory with a URL of ~1,700 chars.

URL_length Execution_time Free_memory 52 2964 1839 65 908 1826 78 1117 1813 91 1123 1800 104 606 1787 117 1753 1774 130 1129 1761 143 412 1748 156 824 1735 169 527 1722 182 529 1709 195 841 1696 208 435 1683 221 415 1670 234 445 1657 247 530 1644 260 434 1631 273 1795 1618 286 10445 1605 299 10491 1592 312 10493 1579 325 10545 1566 338 10545 1553 351 10595 1540 364 10597 1527 377 10648 1514 390 10653 1501 403 10681 1488 416 10666 1475 429 10737 1462 442 10730 1449 455 10792 1436 468 877 1423 481 8896 1410 494 4455 1397 507 665 1384 520 675 1371 533 799 1358 546 695 1345 559 3095 1332 572 749 1319 585 726 1306 598 738 1293 611 789 1280 624 755 1267 637 767 1254 650 706 1241 663 792 1228 676 796 1215 689 835 1202 702 826 1189 715 834 1176 728 1289 1163 741 847 1150 754 957 1137 767 863 1124 780 864 1111 793 1474 1098 806 1499 1085 819 1474 1072 832 1537 1059 845 150 1046 858 151 1033 871 142 1020 884 140 1007 897 141 994 910 149 981 923 151 968 936 150 955 949 151 942 962 150 929 975 143 916 988 141 903 1001 151 890

Code: PS: If you don't want to install the MemoryFree library, just comment the associated include and the freeMemory() call.

#include <Bridge.h>
#include <HttpClient.h>
#include <MemoryFree.h>

String url;

HttpClient client;

void setup() {
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW);

  Bridge.begin();
  Serial.begin(9600);

  while(!Serial);
  Serial.println("Starting...");
  url="http://echo.jsontest.com/u?u=1234567890";
}

void loop() {
  url+="&u=1234567890";
  long start=millis();
  client.get(url);
  long delay=millis()-start;
  Serial.print(url.length());
  Serial.print("\t");
  Serial.print(String(delay));
  Serial.print("\t");
  Serial.println(freeMemory());
}

Copied from original issue: arduino/Arduino#1924

arduino-libraries / Bridge

YUN: Errors executing Curl or Client.get via Bridge: different behaviors based on length of commands/URL #10