• Important Note for ESP32_S3
• Important Change from v1.2.0
• Why do we need this AsyncTCP_SSL library
  • Features
  • Why Async is better
  • Currently supported Boards
• Changelog
• Prerequisites
• Installation
  • Use Arduino Library Manager
  • Manual Install
  • VS Code & PlatformIO
• Note for Platform IO using ESP32 LittleFS
• HOWTO Fix Multiple Definitions Linker Error
• Note for Platform IO using ESP32 LittleFS
• HOWTO Use analogRead() with ESP32 running WiFi and/or BlueTooth (BT/BLE)
  • 1. ESP32 has 2 ADCs, named ADC1 and ADC2
  • 2. ESP32 ADCs functions
  • 3. ESP32 WiFi uses ADC2 for WiFi functions
• Original documentation
  • AsyncSSLClient
• Examples
  • 1. multiFileProject
• Debug Terminal Output Samples
  • 1. AsyncHTTPSRequest_ESP on ESP32_DEV
  • 2. AsyncHTTPSRequest_ESP on ESP32S2_DEV
  • 3. AsyncHTTPSRequest_ESP on ESP32C3_DEV
  • 4. AsyncHTTPSRequest_ESP_WiFiManager on ESP32_DEV
  • 5. AsyncHTTPSRequest_ESP_Multi on ESP32S3_DEV
• Debug
• Troubleshooting
• Issues
• TO DO
• DONE
• Contributions and Thanks
• Contributing
• License
• Copyright

Don't use ESP32_S3 with core v2.0.4. Check already fixed ESP32-S3 Powercycling right after uploading a sketch using Arduino IDE and Arduino Core 2.0.4 #7165

ESP32_S3 is OK now with core v2.0.5

Please have a look at HOWTO Fix Multiple Definitions Linker Error

This library is based on, modified from:

1. Hristo Gochkov's AsyncTCP
2. Maarten Fremouw's AsyncTCP.
3. Thorsten von Eicken's AsyncTCP

to apply the better and faster asynchronous feature of the powerful AsyncTCP Library with SSL, and will be the base for future and more advanced Async libraries for ESP32, such as AsyncSSLWebServer, AsyncHTTPSRequest, etc.

• Using asynchronous network means that you can handle more than one connection at the same time
• You are called once the request is ready and parsed
• When you send the response, you are immediately ready to handle other connections while the server is taking care of sending the response in the background
• Speed is OMG
• Easy to use API, HTTP Basic and Digest MD5 Authentication (default), ChunkedResponse
• Easily extensible to handle any type of content
• Supports Continue 100
• Async WebSocket plugin offering different locations without extra servers or ports
• Async EventSource (Server-Sent Events) plugin to send events to the browser
• URL Rewrite plugin for conditional and permanent url rewrites
• ServeStatic plugin that supports cache, Last-Modified, default index and more
• Simple template processing engine to handle templates

1. ESP32 boards, such as ESP32_DEV, etc.
2. ESP32_S2-based boards, such as ESP32S2_DEV, ESP32_S2 Saola, etc.
3. ESP32_C3-based boards, such as ESP32C3_DEV, etc.
4. ESP32_S3-based boards, such as ESP32S3_DEV, etc., using ESP32 core v2.0.3 or v2.0.5+

1. Arduino IDE 1.8.19+ for Arduino.
2. ESP32 Core 2.0.5+ for ESP32-based boards. for ESP32, ESP32_S2, ESP32_C3
3. ESP32 Core 2.0.4 can't be used for ESP32_S3-based boards. Check already fixed ESP32-S3 Powercycling right after uploading a sketch using Arduino IDE and Arduino Core 2.0.4 #7165

The best and easiest way is to use Arduino Library Manager. Search for AsyncTCP_SSL, then select / install the latest version. You can also use this link for more detailed instructions.

Another way to install is to:

1. Navigate to AsyncTCP_SSL page.
2. Download the latest release AsyncTCP_SSL-main.zip.
3. Extract the zip file to AsyncTCP_SSL-main directory
4. Copy whole AsyncTCP_SSL-main folder to Arduino libraries' directory such as ~/Arduino/libraries/.

1. Install VS Code
2. Install PlatformIO
3. Install AsyncTCP_SSL library by using Library Manager. Search for AsyncTCP_SSL in Platform.io Author's Libraries
4. Use included platformio.ini file from examples to ensure that all dependent libraries will installed automatically. Please visit documentation for the other options and examples at Project Configuration File

In Platform IO, to fix the error when using LittleFS_esp32 v1.0 for ESP32-based boards with ESP32 core v1.0.4- (ESP-IDF v3.2-), uncomment the following line

from

//#define CONFIG_LITTLEFS_FOR_IDF_3_2   /* For old IDF - like in release 1.0.4 */

to

#define CONFIG_LITTLEFS_FOR_IDF_3_2   /* For old IDF - like in release 1.0.4 */

It's advisable to use the latest LittleFS_esp32 v1.0.5+ to avoid the issue.

Thanks to Roshan to report the issue in Error esp_littlefs.c 'utime_p'

The current library implementation, using xyz-Impl.h instead of standard xyz.cpp, possibly creates certain Multiple Definitions Linker error in certain use cases.

You can include this .hpp file

// Can be included as many times as necessary, without `Multiple Definitions` Linker Error
#include "AsyncTCP_SSL.hpp"     //https://github.com/khoih-prog/AsyncTCP_SSL

in many files. But be sure to use the following .h file in just 1 .h, .cpp or .ino file, which must not be included in any other file, to avoid Multiple Definitions Linker Error

// To be included only in main(), .ino with setup() to avoid `Multiple Definitions` Linker Error
#include "AsyncTCP_SSL.h"       //https://github.com/khoih-prog/AsyncTCP_SSL

Check the new multiFileProject example for a HOWTO demo.

In Platform IO, to fix the error when using LittleFS_esp32 v1.0 for ESP32-based boards with ESP32 core v1.0.4- (ESP-IDF v3.2-), uncomment the following line

from

//#define CONFIG_LITTLEFS_FOR_IDF_3_2   /* For old IDF - like in release 1.0.4 */

to

#define CONFIG_LITTLEFS_FOR_IDF_3_2   /* For old IDF - like in release 1.0.4 */

It's advisable to use the latest LittleFS_esp32 v1.0.5+ to avoid the issue.

Thanks to Roshan to report the issue in Error esp_littlefs.c 'utime_p'

Please have a look at ESP_WiFiManager Issue 39: Not able to read analog port when using the autoconnect example to have more detailed description and solution of the issue.

• ADC1 controls ADC function for pins GPIO32-GPIO39
• ADC2 controls ADC function for pins GPIO0, 2, 4, 12-15, 25-27

Look in file adc_common.c

In ADC2, there're two locks used for different cases:

1. lock shared with app and Wi-Fi: ESP32: When Wi-Fi using the ADC2, we assume it will never stop, so app checks the lock and returns immediately if failed. ESP32S2: The controller's control over the ADC is determined by the arbiter. There is no need to control by lock.

2. lock shared between tasks: when several tasks sharing the ADC2, we want to guarantee all the requests will be handled. Since conversions are short (about 31us), app returns the lock very soon, we use a spinlock to stand there waiting to do conversions one by one.

adc2_spinlock should be acquired first, then adc2_wifi_lock or rtc_spinlock.

• In order to use ADC2 for other functions, we have to acquire complicated firmware locks and very difficult to do
• So, it's not advisable to use ADC2 with WiFi/BlueTooth (BT/BLE).
• Use ADC1, and pins GPIO32-GPIO39
• If somehow it's a must to use those pins serviced by ADC2 (GPIO0, 2, 4, 12, 13, 14, 15, 25, 26 and 27), use the fix mentioned at the end of ESP_WiFiManager Issue 39: Not able to read analog port when using the autoconnect example to work with ESP32 WiFi/BlueTooth (BT/BLE).

For ESP32, check AsyncTCP Library

This is a fully asynchronous SSL TCP library, aimed at enabling trouble-free, multi-connection network environment for Espressif's ESP32 MCUs.

The base classes on which everything else is built. They expose all possible scenarios, but are really raw and require more skills to use.

1. multiFileProject. New

Following is the debug terminal when running example AsyncHTTPSRequest_ESP on ESP32_DEV to demonstrate the operation of SSL Async HTTPS request, using AsyncTCP_SSL Library.

Starting AsyncHTTPSRequest_ESP using ESP32_DEV
AsyncTCP_SSL v1.3.1
AsyncHTTPSRequest_Generic v2.1.2
Connecting to WiFi SSID: HueNet1
.......
AsyncHTTPSRequest @ IP : 192.168.2.133

**************************************
abbreviation: EDT
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T01:35:32.451975-04:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-13T07:00:00+00:00
dst_offset: 3600
dst_until: 2022-11-06T06:00:00+00:00
raw_offset: -18000
timezone: America/Toronto
unixtime: 1663479332
utc_datetime: 2022-09-18T05:35:32.451975+00:00
utc_offset: -04:00
week_number: 37
**************************************
HHHHHH
**************************************
abbreviation: EDT
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T01:36:31.992595-04:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-13T07:00:00+00:00
dst_offset: 3600
dst_until: 2022-11-06T06:00:00+00:00
raw_offset: -18000
timezone: America/Toronto
unixtime: 1663479391
utc_datetime: 2022-09-18T05:36:31.992595+00:00
utc_offset: -04:00
week_number: 37

Following is the debug terminal when running example AsyncHTTPSRequest_ESP on ESP32S2_DEV to demonstrate the operation of SSL Async HTTPS request, using AsyncTCP_SSL Library.

Starting AsyncHTTPSRequest_ESP using ESP32S2_DEV
AsyncTCP_SSL v1.3.1
AsyncHTTPSRequest_Generic v2.1.2
Connecting to WiFi SSID: HueNet1
.......
AsyncHTTPSRequest @ IP : 192.168.2.79
[ATCP] _handle_async_event: LWIP_TCP_DNS = 0x3FFE4E24
[ATCP] _handle_async_event: LWIP_TCP_DNS, name = worldtimeapi.org , IP = 213.188.196.246
[ATCP] _handle_async_event: LWIP_TCP_CONNECTED = 0x3FFE4E24 0x3FFE5024
[ATCP] _handle_async_event: LWIP_TCP_CONNECTED =  0
[ATCP] _handle_async_event: LWIP_TCP_SENT = 0x3FFE5024
[ATCP] _sent: len = 305
[ATCP] _handle_async_event: LWIP_TCP_RECV = 0x3FFE5024
[ATCP] _recv: tot_len = 1436
[ATCP] _handle_async_event: LWIP_TCP_RECV = 0x3FFE5024
[ATCP] _recv: tot_len = 1436
[ATCP] _handle_async_event: LWIP_TCP_RECV = 0x3FFE5024
[ATCP] _recv: tot_len = 1242
[ATCP] _handle_async_event: LWIP_TCP_SENT = 0x3FFE5024
[ATCP] _sent: len = 107
[ATCP] _handle_async_event: LWIP_TCP_SENT = 0x3FFE5024
[ATCP] _sent: len = 6
[ATCP] _handle_async_event: LWIP_TCP_SENT = 0x3FFE5024
[ATCP] _sent: len = 45
[ATCP] _handle_async_event: LWIP_TCP_RECV = 0x3FFE5024
[ATCP] _recv: tot_len = 51
[ATCP] _handle_async_event: LWIP_TCP_SENT = 0x3FFE5024
[ATCP] _sent: len = 106
[ATCP] _handle_async_event: LWIP_TCP_RECV = 0x3FFE5024
[ATCP] _recv: tot_len = 1016
**************************************
abbreviation: EDT
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T01:46:31.858783-04:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-13T07:00:00+00:00
dst_offset: 3600
dst_until: 2022-11-06T06:00:00+00:00
raw_offset: -18000
timezone: America/Toronto
unixtime: 1663479991
utc_datetime: 2022-09-18T05:46:31.858783+00:00
utc_offset: -04:00
week_number: 37
**************************************

Following is the debug terminal when running example AsyncHTTPSRequest_ESP on ESP32C3_DEV to demonstrate the operation of SSL Async HTTPS request, using AsyncTCP_SSL Library.

Starting AsyncHTTPSRequest_ESP using ESP32C3_DEV
AsyncTCP_SSL v1.3.1
AsyncHTTPSRequest_Generic v2.1.2
Connecting to WiFi SSID: HueNet1
.........
AsyncHTTPSRequest @ IP : 192.168.2.80
**************************************
abbreviation: EDT
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T01:35:32.451975-04:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-13T07:00:00+00:00
dst_offset: 3600
dst_until: 2022-11-06T06:00:00+00:00
raw_offset: -18000
timezone: America/Toronto
unixtime: 1663479332
utc_datetime: 2022-09-18T05:35:32.451975+00:00
utc_offset: -04:00
week_number: 37
**************************************

Following is the debug terminal when running example AsyncHTTPSRequest_ESP_WiFiManager on ESP32_DEV to demonstrate the operation of SSL Async HTTPS request, using AsyncTCP_SSL Library, and ESPAsync_WiFiManager Library

Starting AsyncHTTPSRequest_ESP_WiFiManager using LittleFS on ESP32_DEV
ESPAsync_WiFiManager v1.14.1
AsyncTCP_SSL v1.3.1
AsyncHTTPSRequest_Generic v2.1.2
Stored: SSID = HueNet1, Pass = 12345678
Got stored Credentials. Timeout 120s
ConnectMultiWiFi in setup
After waiting 11.38 secs more in setup(), connection result is connected. Local IP: 192.168.2.232
H
**************************************
abbreviation: EDT
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T01:36:31.992595-04:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-13T07:00:00+00:00
dst_offset: 3600
dst_until: 2022-11-06T06:00:00+00:00
raw_offset: -18000
timezone: America/Toronto
unixtime: 1663479391
utc_datetime: 2022-09-18T05:36:31.992595+00:00
utc_offset: -04:00
week_number: 37
**************************************
H

Following is the debug terminal when running example AsyncHTTPSRequest_ESP_Multi on ESP32S3_DEV on ESP32 core v2.0.5 to demonstrate the operation of SSL Async HTTPS request, using AsyncTCP_SSL Library

Starting AsyncHTTPSRequest_ESP_Multi on ESP32S3_DEV
AsyncTCP_SSL v1.3.1
AsyncHTTPSRequest_Generic v2.1.2
Connecting to WiFi SSID: HueNet1
...
AsyncHTTPSRequest @ IP : 192.168.2.187

Sending request: https://worldtimeapi.org/api/timezone/Europe/Prague.txt

Sending request: https://www.myexternalip.com/raw
[AHTTPS] _onError handler SSL error = OK
[AHTTPS] _onError handler SSL error = OK

**************************************
[AHTTPS] Response Code =  HTTP OK

**************************************
aaa.bbb.ccc.ddd
**************************************

**************************************
[AHTTPS] Response Code =  HTTP OK

**************************************
abbreviation: CEST
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T07:50:04.395849+02:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-27T01:00:00+00:00
dst_offset: 3600
dst_until: 2022-10-30T01:00:00+00:00
raw_offset: 3600
timezone: Europe/Prague
unixtime: 1663480204
utc_datetime: 2022-09-18T05:50:04.395849+00:00
utc_offset: +02:00
week_number: 37
**************************************

Sending request: https://worldtimeapi.org/api/timezone/America/Toronto.txt

**************************************
[AHTTPS] Response Code =  HTTP OK

**************************************
abbreviation: EDT
client_ip: aaa.bbb.ccc.ddd
datetime: 2022-09-18T01:50:05.382100-04:00
day_of_week: 0
day_of_year: 261
dst: true
dst_from: 2022-03-13T07:00:00+00:00
dst_offset: 3600
dst_until: 2022-11-06T06:00:00+00:00
raw_offset: -18000
timezone: America/Toronto
unixtime: 1663480205
utc_datetime: 2022-09-18T05:50:05.382100+00:00
utc_offset: -04:00
week_number: 37
**************************************
H

Debug is enabled by default on Serial.

You can also change the debugging level _ASYNC_TCP_SSL_LOGLEVEL_ from 0 to 4 in the sketch

#define _ASYNC_TCP_SSL_LOGLEVEL_     1

If you get compilation errors, more often than not, you may need to install a newer version of the core for Arduino boards.

Sometimes, the library will only work if you update the board core to the latest version because I am using newly added functions.

Submit issues to: AsyncTCP_SSL issues

1. Search for bug and improvement.
2. Similar Async SSL libraries for ESP8266, STM32, Portenta_H7 and many other boards
3. Permit both HTTP and HTTPS

1. Add support to ESP32 using SSL
2. Add Table of Contents
3. Add debug feature
4. Fix multiple-definitions linker error
5. Add examples
6. Remove hard-code if possible
7. Improve debug messages by adding functions to display error/state messages instead of cryptic error/state number
8. Add support to ESP32_S3, using ESP32 core v2.0.3 or v2.0.5+. Don't use ESP32_S3 with core v2.0.4. Check already fixed ESP32-S3 Powercycling right after uploading a sketch using Arduino IDE and Arduino Core 2.0.4 #7165
9. Increase ASYNC_QUEUE_LENGTH to default 512 from 32 and make it user-configurable
10. Increase ASYNC_TCP_PRIORITY to default 10 from 3, and make it user-configurable

Many thanks for everyone for bug reporting, new feature suggesting, testing and contributing to the development of this library.

1. Based on and modified from Hristo Gochkov's AsyncTCP. Many thanks to Hristo Gochkov for great AsyncTCP Library
2. Based on Maarten Fremouw's AsyncTCP Library.
3. Based on Thorsten von Eicken's AsyncTCP Library.

⭐️⭐️ Hristo Gochkov

Maarten Fremouw

Thorsten von Eicken

If you want to contribute to this project:

• Report bugs and errors
• Ask for enhancements
• Create issues and pull requests
• Tell other people about this library

• The library is licensed under LGPLv3

• Copyright (c) 2016- Hristo Gochkov
• Copyright (c) 2019- Maarten Fremouw
• Copyright (c) 2019- Thorsten von Eicken
• Copyright (c) 2021- Khoi Hoang