@ -1198,7 +1198,7 @@ Also, if you want to stop AutoConnect completely when the captive portal is time
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<p>There is another option related to timeout in AutoConnectConfig. It can make use of the captive portal function even after a timeout. The <ahref="apiconfig.html#retainlportal"><strong>AutoConnectConfig::retainPortal</strong></a> option will not stop the SoftAP when the captive portal is timed out. If you enable the ratainPortal option, you can try to connect to the AP at any time while continuing to sketch execution with offline even after the captive portal timed-out. Compared to the above code specified no option with the following example code, the captive portal will remain available even after a timeout without changing the logic of the sketch.</p>
<p>There is another option related to timeout in AutoConnectConfig. It can make use of the captive portal function even after a timeout. The <ahref="apiconfig.html#retainportal"><strong>AutoConnectConfig::retainPortal</strong></a> option will not stop the SoftAP when the captive portal is timed out. If you enable the ratainPortal option, you can try to connect to the AP at any time while continuing to sketch execution with offline even after the captive portal timed-out. Compared to the above code specified no option with the following example code, the captive portal will remain available even after a timeout without changing the logic of the sketch.</p>
<pclass="admonition-title">Connection request after timed-out</p>
<p>With the <strong>retainPortal</strong>, even if AutoConnect::begin in the setup() is timed out, you can execute the sketch and the portal function as a WiFi connection attempt by calling AutoConnect::handleClient in the loop().</p>
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<divclass="admonition info">
<pclass="admonition-title">All unresolved addresses redirects to /_ac</p>
<p>If you enable the <strong>retainPortal</strong> option, <strong>all unresolved URIs will be redirected to <code>SoftAPIP/_ac</code></strong>. It happens frequently as client devices repeat captive portal probes in particular. To avoid this, you need to exit from the WiFi connection Apps on your device once.</p>
<p>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.</p>
<p>For example, AutoConnect::begin will not exits without the <strong>portalTimeout</strong> while the connection not establishes, but WebServer will start to work. 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 <strong>setup()</strong>, execution control does not pass to the <strong>loop()</strong>.</p>
<p>For example, AutoConnect::begin will not exits without the <strong>portalTimeout</strong> 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 <strong>setup()</strong>, execution control does not pass to the <strong>loop()</strong>.</p>
<p>As different scenes, you may use the <strong>immediateStart</strong> effectively. Equipped the external switch to activate the captive portal with the ESP module, combined with the <strong>portalTime</strong> and the <strong>retainPortal</strong> it will become WiFi active connection feature. You can start AutoConnect::begin at any point in the <strong>loop()</strong>, which allows your sketch can behave both the offline mode and the online mode.</p>
<p>The <strong>retainPortal</strong> 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 <code>SoftAPIP/_ac</code> 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.</p>
<p>Please consider these kinds of influence when you make sketches.</p>
Hieromon Ikasamo
6 years ago