Read corrupted PST/OST files

Read corrupted PST/OST files

Sometimes it may not be possible to read the PST/OST due to some issues. For example, some data blocks may be corrupted. In such cases, exceptions usually arise when calling the EnumerateFolders, EnumerateMessages, GetContents, GetSubfolders, etc. methods. But individual messages or folders may remain undamaged in the storage.

Aspose.Email users can find item identifiers in a hierarchical manner. Further, you can extract items by identifiers. For this purpose, the library offers the following methods:

• PersonalStorage.findMessages(String parentEntryId) - finds the identifiers of messages for the folder.
• PersonalStorage.findSubfolders(String parentEntryId) - finds the identifiers of subfolders for the folder.

Note, that despite the advantages, there are corrupted storages that cannot be read even using these methods.

The following code snippet demonstrates the use of these methods to read corrupted PST/OST files:

try (PersonalStorage pst = PersonalStorage.fromFile(fileName)) {
    exploreCorruptedPst(pst, pst.getRootFolder().getEntryIdString());
}

public static void exploreCorruptedPst(PersonalStorage pst, String rootFolderId) {
    Iterable<String> messageIdList = pst.findMessages(rootFolderId);

    for (String messageId : messageIdList) {
        try {
            MapiMessage msg = pst.extractMessage(messageId);
            System.out.println("- " + msg.getSubject());
        } catch (Exception e) {
            System.out.println("Message reading error. Entry id: " + messageId);
        }
    }

    Iterable<String> folderIdList = pst.findSubfolders(rootFolderId);

    for (String subFolderId : folderIdList) {
        if (subFolderId != rootFolderId) {
            try {
                FolderInfo subfolder = pst.getFolderById(subFolderId);
                System.out.println(subfolder.getDisplayName());
            } catch (Exception e) {
                System.out.println("Message reading error. Entry id: " + subFolderId);
            }

            exploreCorruptedPst(pst, subFolderId);
        }
    }
}

PST file traversal API

The traversal API allows extracting all PST items as far as possible, without throwing out exceptions, even if some data of the original file is corrupted.

Use the PersonalStorage(TraversalExceptionsCallback callback) constructor and the load(String fileName) method instead of the fromFile method.

The constructor allows defining a callback method.

TraversalExceptionsCallback exceptionsCallback = new TraversalExceptionsCallback() {
    @Override
    public void invoke(TraversalAsposeException exception, String itemId) {
        /* Exception handling  code. */
    }
};

try (PersonalStorage pst = new PersonalStorage(exceptionsCallback)) { }

Loading and traversal exceptions will be available through the callback method.

The load method returns ‘true’ if the file has been loaded successfully and further traversal is possible. If a file is corrupted and no traversal is possible, ‘false’ is returned.

if (currentPst.load(inputStream))

The following code sample shows how to implement PST file traversal API into a project:

public static void main(String[] args) {
    TraversalExceptionsCallback exceptionsCallback = new TraversalExceptionsCallback() {
        @Override
        public void invoke(TraversalAsposeException exception, String itemId) {
            /* Exception handling  code. */
        }
    };

    try (PersonalStorage pst = new PersonalStorage(exceptionsCallback)) {
        if (pst.load("test.pst")) {
            getAllMessages(pst, pst.getRootFolder());
        }
    }
}

private static void getAllMessages(PersonalStorage pst, FolderInfo folder) {
    for (String messageEntryId : folder.enumerateMessagesEntryId()) {
        MapiMessage message = pst.extractMessage(messageEntryId);
    }
    for (FolderInfo subFolder : folder.getSubFolders()) {
        getAllMessages(pst, subFolder);
    }
}