Add a rough "!history" email command to get an entire object history via email

Summary:
See PHI505. Ref T13124. If you're an agent of a hostile state trying to exfiltrate corporate secrets, you might find yourself foiled if Phabricator is secured behind a VPN.

To assist users in this situation, provide a "!history" command which will dump the entire history of an object in a nice text format and get through the troublesome VPN.

Some issues with this:

  - You currently get all the "X added a comment." up top, and then all the comments below. This isn't terribly useful.
  - This goes through the "Must Encrypt" flag, but possibly should not? (On the other hand, this is a pretty willful way to bypass it the flag.)

Test Plan: Used `bin/mail receive-test ...` to send `!history` commands, got somewhat-useful response mail.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13124

Differential Revision: https://secure.phabricator.com/D19372

src/applications/transactions/constants/PhabricatorTransactions.php

@@ -15,6 +15,7 @@ final class PhabricatorTransactions extends Phobject {
   const TYPE_CREATE = 'core:create';
   const TYPE_COLUMNS = 'core:columns';
   const TYPE_SUBTYPE = 'core:subtype';
+  const TYPE_HISTORY = 'core:history';
 
   const COLOR_RED         = 'red';
   const COLOR_ORANGE      = 'orange';

src/applications/transactions/editor/PhabricatorApplicationTransactionEditor.php

@@ -83,6 +83,7 @@ abstract class PhabricatorApplicationTransactionEditor
   private $webhookMap = array();
 
   private $transactionQueue = array();
+  private $sendHistory = false;
 
   const STORAGE_ENCODING_BINARY = 'binary';
 
@@ -300,6 +301,7 @@ abstract class PhabricatorApplicationTransactionEditor
     $types = array();
 
     $types[] = PhabricatorTransactions::TYPE_CREATE;
+    $types[] = PhabricatorTransactions::TYPE_HISTORY;
 
     if ($this->object instanceof PhabricatorEditEngineSubtypeInterface) {
       $types[] = PhabricatorTransactions::TYPE_SUBTYPE;
@@ -377,6 +379,7 @@ abstract class PhabricatorApplicationTransactionEditor
 
     switch ($type) {
       case PhabricatorTransactions::TYPE_CREATE:
+      case PhabricatorTransactions::TYPE_HISTORY:
         return null;
       case PhabricatorTransactions::TYPE_SUBTYPE:
         return $object->getEditEngineSubtype();
@@ -468,6 +471,7 @@ abstract class PhabricatorApplicationTransactionEditor
       case PhabricatorTransactions::TYPE_TOKEN:
       case PhabricatorTransactions::TYPE_INLINESTATE:
       case PhabricatorTransactions::TYPE_SUBTYPE:
+      case PhabricatorTransactions::TYPE_HISTORY:
         return $xaction->getNewValue();
       case PhabricatorTransactions::TYPE_SPACE:
         $space_phid = $xaction->getNewValue();
@@ -520,6 +524,7 @@ abstract class PhabricatorApplicationTransactionEditor
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_CREATE:
+      case PhabricatorTransactions::TYPE_HISTORY:
         return true;
       case PhabricatorTransactions::TYPE_CUSTOMFIELD:
         $field = $this->getCustomFieldForTransaction($object, $xaction);
@@ -604,6 +609,7 @@ abstract class PhabricatorApplicationTransactionEditor
         $field = $this->getCustomFieldForTransaction($object, $xaction);
         return $field->applyApplicationTransactionInternalEffects($xaction);
       case PhabricatorTransactions::TYPE_CREATE:
+      case PhabricatorTransactions::TYPE_HISTORY:
       case PhabricatorTransactions::TYPE_SUBTYPE:
       case PhabricatorTransactions::TYPE_TOKEN:
       case PhabricatorTransactions::TYPE_VIEW_POLICY:
@@ -665,6 +671,7 @@ abstract class PhabricatorApplicationTransactionEditor
         $field = $this->getCustomFieldForTransaction($object, $xaction);
         return $field->applyApplicationTransactionExternalEffects($xaction);
       case PhabricatorTransactions::TYPE_CREATE:
+      case PhabricatorTransactions::TYPE_HISTORY:
       case PhabricatorTransactions::TYPE_SUBTYPE:
       case PhabricatorTransactions::TYPE_EDGE:
       case PhabricatorTransactions::TYPE_TOKEN:
@@ -800,6 +807,9 @@ abstract class PhabricatorApplicationTransactionEditor
       case PhabricatorTransactions::TYPE_SPACE:
         $this->scrambleFileSecrets($object);
         break;
+      case PhabricatorTransactions::TYPE_HISTORY:
+        $this->sendHistory = true;
+        break;
     }
   }
 
@@ -1317,6 +1327,13 @@ abstract class PhabricatorApplicationTransactionEditor
       $this->publishFeedStory($object, $xactions, $mailed);
     }
 
+    if ($this->sendHistory) {
+      $history_mail = $this->buildHistoryMail($object);
+      if ($history_mail) {
+        $messages[] = $history_mail;
+      }
+    }
+
     // NOTE: This actually sends the mail. We do this last to reduce the chance
     // that we send some mail, hit an exception, then send the mail again when
     // retrying.
@@ -2557,6 +2574,25 @@ abstract class PhabricatorApplicationTransactionEditor
       $unexpandable = array();
     }
 
+    $messages = $this->buildMailWithRecipients(
+      $object,
+      $xactions,
+      $email_to,
+      $email_cc,
+      $unexpandable);
+
+    $this->runHeraldMailRules($messages);
+
+    return $messages;
+  }
+
+  private function buildMailWithRecipients(
+    PhabricatorLiskDAO $object,
+    array $xactions,
+    array $email_to,
+    array $email_cc,
+    array $unexpandable) {
+
     $targets = $this->buildReplyHandler($object)
       ->setUnexpandablePHIDs($unexpandable)
       ->getMailTargets($email_to, $email_cc);
@@ -2603,8 +2639,6 @@ abstract class PhabricatorApplicationTransactionEditor
       }
     }
 
-    $this->runHeraldMailRules($messages);
-
     return $messages;
   }
 
@@ -3671,6 +3705,7 @@ abstract class PhabricatorApplicationTransactionEditor
       'mailMutedPHIDs',
       'webhookMap',
       'silent',
+      'sendHistory',
     );
   }
 
@@ -4328,4 +4363,32 @@ abstract class PhabricatorApplicationTransactionEditor
     return true;
   }
 
+  private function buildHistoryMail(PhabricatorLiskDAO $object) {
+    $viewer = $this->requireActor();
+    $recipient_phid = $this->getActingAsPHID();
+
+    // Load every transaction so we can build a mail message with a complete
+    // history for the object.
+    $query = PhabricatorApplicationTransactionQuery::newQueryForObject($object);
+    $xactions = $query
+      ->setViewer($viewer)
+      ->withObjectPHIDs(array($object->getPHID()))
+      ->execute();
+    $xactions = array_reverse($xactions);
+
+    $mail_messages = $this->buildMailWithRecipients(
+      $object,
+      $xactions,
+      array($recipient_phid),
+      array(),
+      array());
+    $mail = head($mail_messages);
+
+    // Since the user explicitly requested "!history", force delivery of this
+    // message regardless of their other mail settings.
+    $mail->setForceDelivery(true);
+
+    return $mail;
+  }
+
 }

src/applications/transactions/storage/PhabricatorApplicationTransaction.php

@@ -545,11 +545,18 @@ abstract class PhabricatorApplicationTransaction
       return false;
     }
 
+    $xaction_type = $this->getTransactionType();
+
+    // Always hide requests for object history.
+    if ($xaction_type === PhabricatorTransactions::TYPE_HISTORY) {
+      return true;
+    }
+
     // Hide creation transactions if the old value is empty. These are
-    // transactions like "alice set the task tile to: ...", which are
+    // transactions like "alice set the task title to: ...", which are
     // essentially never interesting.
     if ($this->getIsCreateTransaction()) {
-      switch ($this->getTransactionType()) {
+      switch ($xaction_type) {
         case PhabricatorTransactions::TYPE_CREATE:
         case PhabricatorTransactions::TYPE_VIEW_POLICY:
         case PhabricatorTransactions::TYPE_EDIT_POLICY: