"Cannot allocate an object of abstract type 'HttpClient'

This site is best viewed in a modern browser with JavaScript enabled.

"Cannot allocate an object of abstract type 'HttpClient'

verticalgrain

Hi there,
I'm attempting to connect my esp8266 (wemos d1 mini) to wia. I'm following this tutorial for the esp8166: https://developers.wia.io/v1.0/docs/espressif-esp8266

When I try to verify the sketch, I'm getting the error "Cannot allocate an object of abstract type 'HttpClient'.

I've added the ESP package under "additional boards manager urls", and have made sure the arduinoJSON and arduinoHttpClient packages are installed.

I've tried switching to different versions of the arduinoHttpClient pacakge.

Thanks for any help!

Full error message:

Arduino: 1.8.8 (Mac OS X), Board: "LOLIN(WEMOS) D1 R2 & mini, 80 MHz, Flash, Enabled, 4M (no SPIFFS), v2 Lower Memory, Disabled, None, Only Sketch, 921600"

In file included from /Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/ArduinoHttpClient.h:8:0,
from /Users/jamie/Documents/Projects/Remoter Box/wia_test_event/wia_test_event.ino:4:
/Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/HttpClient.h: In member function 'virtual void HttpClient::flush()':
/Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/HttpClient.h:296:50: error: return-statement with a value, in function returning 'void' [-fpermissive]
virtual void flush() { return iClient->flush(); };
^
/Users/jamie/Documents/Projects/Remoter Box/wia_test_event/wia_test_event.ino: At global scope:
wia_test_event:18:56: error: cannot allocate an object of abstract type 'HttpClient'
HttpClient httpClient = HttpClient(client, server, port);
^
In file included from /Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/ArduinoHttpClient.h:8:0,
from /Users/jamie/Documents/Projects/Remoter Box/wia_test_event/wia_test_event.ino:4:
/Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/HttpClient.h:39:7: note: because the following virtual functions are pure within 'HttpClient':
class HttpClient : public Client
^
In file included from /Users/jamie/Applications/Arduino.app/Contents/Java/hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/WiFiClient.h:27:0,
from /Users/jamie/Applications/Arduino.app/Contents/Java/hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/ESP8266WiFi.h:39,
from /Users/jamie/Documents/Projects/Remoter Box/wia_test_event/wia_test_event.ino:3:
/Users/jamie/Applications/Arduino.app/Contents/Java/hardware/esp8266com/esp8266/cores/esp8266/Client.h:29:21: note: virtual int Client::connect(const IPAddress&, uint16_t)
virtual int connect(CONST IPAddress& ip, uint16_t port) =0;
^
/Users/jamie/Applications/Arduino.app/Contents/Java/hardware/esp8266com/esp8266/cores/esp8266/Client.h:37:22: note: virtual bool Client::flush(unsigned int)
virtual bool flush(unsigned int maxWaitMs = 0) = 0;
^
/Users/jamie/Applications/Arduino.app/Contents/Java/hardware/esp8266com/esp8266/cores/esp8266/Client.h:38:22: note: virtual bool Client::stop(unsigned int)
virtual bool stop(unsigned int maxWaitMs = 0) = 0;
^
wia_test_event:18:12: error: cannot declare variable 'httpClient' to be of abstract type 'HttpClient'
HttpClient httpClient = HttpClient(client, server, port);
^
In file included from /Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/ArduinoHttpClient.h:8:0,
from /Users/jamie/Documents/Projects/Remoter Box/wia_test_event/wia_test_event.ino:4:
/Users/jamie/Documents/Arduino/libraries/ArduinoHttpClient/src/HttpClient.h:39:7: note: since type 'HttpClient' has pure virtual functions
class HttpClient : public Client
^
/Users/jamie/Documents/Projects/Remoter Box/wia_test_event/wia_test_event.ino: In function 'void postToWia(ArduinoJson::JsonObject&)':
wia_test_event:59:14: error: 'class HttpClient' has no member named 'beginBody'
httpClient.beginBody();
^
exit status 1
cannot allocate an object of abstract type 'HttpClient'

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

verticalgrain

I found the cause of the error.

Under the "Tools -> Boards" menu, there are TWO sections for the esp8266 - esp8266 Boards, and esp8266 Modules. Both show lists of boards - my board appeared in both lists. I had selected my board under Boards, when I had the error. When I change my selection to the Modules section, the error went away.

clemo

Hey I have the same problem with my nodeMCU esp8266 board except doing whatyou did doesn't change anything, here's my error.

In file included from C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/ArduinoHttpClient.h:8:0,

             from C:\Users\CLEMO\Documents\Arduino\SoilMoisture3.ino\SoilMoisture3.ino.ino:3:

C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/HttpClient.h: In member function 'virtual void HttpClient::flush()':

C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/HttpClient.h:310:50: error: return-statement with a value, in function returning 'void' [-fpermissive]

 virtual void flush() { return iClient->flush(); };

                                              ^

C:\Users\CLEMO\Documents\Arduino\SoilMoisture3.ino\SoilMoisture3.ino.ino: At global scope:

SoilMoisture3.ino:21:56: error: cannot allocate an object of abstract type 'HttpClient'

HttpClient httpClient = HttpClient(client, server, port);

In file included from C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/ArduinoHttpClient.h:8:0,

             from C:\Users\CLEMO\Documents\Arduino\SoilMoisture3.ino\SoilMoisture3.ino.ino:3:

C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/HttpClient.h:41:7: note: because the following virtual functions are pure within 'HttpClient':

class HttpClient : public Client

In file included from C:\Users\CLEMO\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.5.0-beta3\libraries\ESP8266WiFi\src/WiFiClient.h:27:0,

             from C:\Users\CLEMO\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.5.0-beta3\libraries\ESP8266WiFi\src/ESP8266WiFi.h:39,

             from C:\Users\CLEMO\Documents\Arduino\SoilMoisture3.ino\SoilMoisture3.ino.ino:2:

C:\Users\CLEMO\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.5.0-beta3\cores\esp8266/Client.h:29:21: note: virtual int Client::connect(const IPAddress&, uint16_t)

     virtual int connect(CONST IPAddress& ip, uint16_t port) =0;

                 ^

C:\Users\CLEMO\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.5.0-beta3\cores\esp8266/Client.h:37:22: note: virtual bool Client::flush(unsigned int)

     virtual bool flush(unsigned int maxWaitMs = 0) = 0;

                  ^

C:\Users\CLEMO\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.5.0-beta3\cores\esp8266/Client.h:38:22: note: virtual bool Client::stop(unsigned int)

     virtual bool stop(unsigned int maxWaitMs = 0) = 0;

                  ^

SoilMoisture3.ino:21:12: error: cannot declare variable 'httpClient' to be of abstract type 'HttpClient'

HttpClient httpClient = HttpClient(client, server, port);

In file included from C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/ArduinoHttpClient.h:8:0,

             from C:\Users\CLEMO\Documents\Arduino\SoilMoisture3.ino\SoilMoisture3.ino.ino:3:

C:\Users\CLEMO\Documents\Arduino\libraries\ArduinoHttpClient\src/HttpClient.h:41:7: note: since type 'HttpClient' has pure virtual functions

class HttpClient : public Client

exit status 1
cannot allocate an object of abstract type 'HttpClient'

clemo

So A couple hours later of debugging I found the solution to my problem. It turns out the error was due to using the latest version of "ArduinoHttpClient.h" library so I just chose another older version.