- Refactoring of the mail sending part. Mail queue (table 'queued') is now used also for all test emails.

- More options how to send test emails.
- Fixed problems with pausing a campaign (#593)
- Started rework of transactional sender of templates (#606), however this contains functionality regression at the moment because it does not interpret templates as HBS. It needs HBS option for templates as described in https://github.com/Mailtrain-org/mailtrain/issues/611#issuecomment-502345227

TODO:
- detect sending errors connected to not able to contact the mailer and pause/retry campaing and queued sending - don't mark the recipients as BOUNCED
- add FAILED campaign state and fall into it if sending to campaign consistently fails (i.e. the error with sending is not temporary)
- if the same happends for queued email, delete the message

server/models/blacklist.js

@@ -41,16 +41,17 @@ async function search(context, offset, limit, search) {
 async function add(context, email) {
     enforce(email, 'Email has to be set');
 
-    return await knex.transaction(async tx => {
-        shares.enforceGlobalPermission(context, 'manageBlacklist');
-
-        const existing = await tx('blacklist').where('email', email).first();
-        if (!existing) {
-            await tx('blacklist').insert({email});
-        }
+    shares.enforceGlobalPermission(context, 'manageBlacklist');
 
+    try {
+        await knex('blacklist').insert({email});
         await activityLog.logBlacklistActivity(BlacklistActivityType.ADD, email);
-    });
+    } catch (err) {
+        if (err.code === 'ER_DUP_ENTRY') {
+        } else {
+            throw err;
+        }
+    }
 }
 
 async function remove(context, email) {