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    <p>Multiple thanks to both Alessandro and Etienne for helping me
      with this question. I owe you both a large cold beer (each !) next
      time we meet.<br>
    </p>
    <pre class="moz-signature" cols="72">Med venlig hilsen / Kind regards

Bo Victor Thomsen</pre>
    <div class="moz-cite-prefix">Den 10-01-2021 kl. 04:10 skrev Etienne
      Trimaille:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAMtDFLLtPf8i14QA_iu4S2rT+6m8j++KNn9Uh4LgeL7fOkDLCQ@mail.gmail.com">
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        <div><span class="gmail-pl-s1">The connection API is indeed
            convenient for that : <br>
          </span></div>
        <div><span class="gmail-pl-s1"><br>
          </span></div>
        <div><span class="gmail-pl-s1">metadata</span> <span
            class="gmail-pl-c1">=</span> <span class="gmail-pl-v">QgsProviderRegistry</span>.<span
            class="gmail-pl-en">instance</span>().<span
            class="gmail-pl-en">providerMetadata</span>(<span
            class="gmail-pl-s">'postgres'</span>)</div>
        <div><span class="gmail-pl-s1">connection</span> <span
            class="gmail-pl-c1">=</span> <span class="gmail-pl-s1"></span><span
            class="gmail-pl-s1">metadata</span>.<span
            class="gmail-pl-en">findConnection</span>("the postgis
          connection name")</div>
        <div><span class="gmail-pl-s1">uri</span> <span
            class="gmail-pl-c1">=</span> <span class="gmail-pl-v">QgsDataSourceUri</span>(<span
            class="gmail-pl-s1">connection</span>.<span
            class="gmail-pl-en">uri</span>())</div>
      </div>
      <br>
      <div class="gmail_quote">
        <div dir="ltr" class="gmail_attr">Le sam. 9 janv. 2021 à 22:36,
          Alessandro Pasotti <<a href="mailto:apasotti@gmail.com"
            moz-do-not-send="true">apasotti@gmail.com</a>> a écrit :<br>
        </div>
        <blockquote class="gmail_quote" style="margin:0px 0px 0px
          0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi
          Bo,<br>
          <br>
          you may have a look to<br>
          <a
href="https://qgis.org/pyqgis/master/core/QgsProviderRegistry.html?highlight=decodeuri#qgis.core.QgsProviderRegistry.decodeUri"
            rel="noreferrer" target="_blank" moz-do-not-send="true">https://qgis.org/pyqgis/master/core/QgsProviderRegistry.html?highlight=decodeuri#qgis.core.QgsProviderRegistry.decodeUri</a><br>
          and encodeUri.<br>
          <br>
          Or better: the connections API<br>
          <a
href="https://qgis.org/pyqgis/master/core/QgsAbstractProviderConnection.html"
            rel="noreferrer" target="_blank" moz-do-not-send="true">https://qgis.org/pyqgis/master/core/QgsAbstractProviderConnection.html</a><br>
          <br>
          <br>
          <br>
          On Sat, Jan 9, 2021 at 2:03 PM Bo Victor Thomsen<br>
          <<a href="mailto:bo.victor.thomsen@gmail.com"
            target="_blank" moz-do-not-send="true">bo.victor.thomsen@gmail.com</a>>
          wrote:<br>
          ><br>
          > Ok, this has me stumped.<br>
          ><br>
          > I know, that I can generate a database URI like this 
          (example from cookbook):<br>
          ><br>
          > uri = QgsDataSourceUri()<br>
          > # set host name, port, database name, username and
          password<br>
          > uri.setConnection("localhost", "5432", "dbname", "johny",
          "xxx")<br>
          > # set database schema, table name, geometry column and
          optionally<br>
          > # subset (WHERE clause)<br>
          > uri.setDataSource("public", "roads", "the_geom", "cityid
          = 2643")<br>
          ><br>
          > vlayer = QgsVectorLayer(uri.uri(False), "layer name you
          like", "postgres")<br>
          ><br>
          ><br>
          > But I would like to use information from a already
          defined Datasource connection from the Datamanager dialog.<br>
          ><br>
          > I suspect, that there must be a
          "QgsSettingsConvertToUri_or_whatever_it_is_called()" function
          that uses a  QGS settings address  (ex. like
          "/PostgreSQL/connections/MyDatabase" for a Postgresql database
          connection)  as input and automatically convert the settings
          values to a URI string.<br>
          ><br>
          > Is there anyone, that can point me in the right direction
          ?<br>
          ><br>
          > --<br>
          ><br>
          > Med venlig hilsen / Kind regards<br>
          ><br>
          > Bo Victor Thomsen<br>
          ><br>
          > _______________________________________________<br>
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          <br>
          <br>
          <br>
          -- <br>
          Alessandro Pasotti<br>
          QCooperative:  <a href="http://www.qcooperative.net"
            rel="noreferrer" target="_blank" moz-do-not-send="true">www.qcooperative.net</a><br>
          ItOpen:   <a href="http://www.itopen.it" rel="noreferrer"
            target="_blank" moz-do-not-send="true">www.itopen.it</a><br>
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