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AutoConnect::begin logic sequence
Several parameters as follows of AutoConnectConfig affect the behavior of AutoConnect::begin function. Each parameter affects the behaves in interacted order with the priority and apply to the logic sequence of AutoConnect::begin.
- immediateStart : The captive portal start immediately, without first WiFi.begin.
- autoReconenct : Attempt re-connect with past SSID by saved credential.
- portalTimeout : Time out limit for the portal.
- retainPortal : Keep DNS server functioning for the captive portal.
You can use these parameters in combination with sketch requirements and need to understand correctly the behavior caused by the parameters. The following chart shows the AutoConnect::begin logic sequence including the effect of these parameters.
For example, AutoConnect::begin will not exits without the portalTimeout while the connection not establishes, but WebServer will start to work. A DNS server that detects the probe of the captive portal is also effective. So, your sketch may work seemingly, but it will close with inside a loop of the AutoConnect::begin function. Especially when invoking AutoConnect::begin in the setup(), execution control does not pass to the loop().
As different scenes, you may use the immediateStart effectively. Equipped the external switch to activate the captive portal with the ESP module, combined with the portalTime and the retainPortal it will become WiFi active connection feature. You can start AutoConnect::begin at any point in the loop(), which allows your sketch can behave both the offline mode and the online mode.
The retainPortal option allows the DNS server to continue operation after exiting from AutoConnect::begin. AutoConnect traps captive portal detection from the client and redirects it to the AutoConnect menu. That trap will answer all unresolved addresses with SoftAP's IP address. If the URI handler for the source request is undefined, it returns a 302 response with SoftAPIP/_ac to the client. This is the mechanism of AutoConnect's captive portal. Captive portal probes will frequently occur while you are attempting on the client device's WiFi connection Apps and these implementations are varied each OS, so it not realistic to identify all probing URIs. Therefore, while retainPortal is enabled, it is not preferable to executing the sketch under the WiFi connection Apps on the client device. (Probably not work correctly) You need to exit from the WiFi connection Apps once.
Please consider these kinds of influence when you make sketches.
!!! info "The AutoConnect::begin 3rd parameter" Another parameter as the 3rd parameter of AutoConnect::begin related to timeout constrains the connection wait time after WiFi.begin. It is the CONNECTED judgment of the above chart that it has an effect.