Ref T32, utility functions for URL/URL list

* keep error messages of failed URLs
* append query

src/blackmisc/network/url.cpp

@@ -96,17 +96,16 @@ namespace BlackMisc
         {
             const QString q(stripQueryString(queryToAppend));
             if (q.isEmpty()) { return m_query;  }
-            if (!hasQuery())
-            {
-                this->setQuery(q);
-            }
-            else
-            {
-                m_query = m_query + "&" + q;
-            }
+            m_query += hasQuery() ? "&" + q : q;
             return m_query;
         }
 
+        QString CUrl::appendQuery(const QString &key, const QString &value)
+        {
+            if (key.isEmpty()) { return m_query; }
+            return this->appendQuery(key + "=" + value);
+        }
+
         QString CUrl::getFullUrl(bool withQuery) const
         {
             if (m_host.isEmpty()) { return ""; }

src/blackmisc/network/url.h

@@ -106,6 +106,9 @@ namespace BlackMisc
             //! Append query
             QString appendQuery(const QString &queryToAppend);
 
+            //! Append query
+            QString appendQuery(const QString &key, const QString &value);
+
             //! Empty
             bool isEmpty() const;
 

src/blackmisc/network/urllist.cpp

@@ -147,8 +147,16 @@ namespace BlackMisc
             if (!failedUrl.isEmpty()) { this->addFailedUrl(failedUrl); }
             if (!hasMoreUrlsToTry()) { return CUrl(); }
             const CUrl url(this->obtainNextUrlWithout(random, this->m_failedUrls));
-            if (CNetworkUtils::canConnect(url)) { return url; }
-            if (addFailedUrl(url)) { return obtainNextWorkingUrl(); }
+            QString msg;
+            if (CNetworkUtils::canConnect(url, msg)) { return url; }
+            if (addFailedUrl(url))
+            {
+                if (!msg.isEmpty())
+                {
+                    this->m_errorMsgs.append(QString("URL: %1 error: ").arg(url.toQString(), msg));
+                }
+                return obtainNextWorkingUrl();
+            }
             return CUrl();
         }
 

src/blackmisc/network/urllist.h

@@ -102,13 +102,17 @@ namespace BlackMisc
             //! Next working URL, test if it can be connected
             CUrl obtainNextWorkingUrl( bool random = false, const CUrl &failedUrl = CUrl());
 
+            //! Get the error messages
+            const QStringList &getErrorMessages() const { return m_errorMsgs; }
+
             //! Reset failed URL, allows to set an optional new number of max.trials
             void reset(int maxTrials = -1);
 
         private:
             int m_currentIndexDistributedLoad = -1; //!< index for random access
-            int m_maxTrials = 2;                    //!< number of max trials
-            CUrlList m_failedUrls;
+            int m_maxTrials = 2;     //!< number of max trials
+            CUrlList m_failedUrls;   //!< failed tested URLs
+            QStringList m_errorMsgs; //!< error messages while testing;
         };
 
     } //namespace