December 28, 2023

Blogger Importer Plugin

Imports posts, images, comments, and categories (blogger tags) from a Blogger blog then migrates authors to WordPress users.

The Blogger Importer imports your blog data from a Google Blogger site into a WordPress.org installation.

Items imported

Categories
Posts (published, scheduled and draft)
Comments (not spam)
Images

Items not imported

Pages
Widgets/Widget Data
Templates/Theme
Comment and author Avatars

Reference

https://www.simplepie.org/

The following were referenced for implementing the images and links

https://wordpress.org/plugins/remote-images-grabber/
http://notions.okuda.ca/wordpress-plugins/blogger-image-import/
https://wordpress.org/plugins/cache-images/
https://wordpress.org/plugins/tumblr-importer/
https://core.trac.wordpress.org/ticket/14525
https://wpengineer.com/1735/easier-better-solutions-to-get-pictures-on-your-posts/
https://web.archive.org/web/20211121020918/http://www.velvetblues.com/web-development-blog/wordpress-plugin-update-urls/
http://wordpress.stackexchange.com/questions//media-sideload-image-file-name (not working)
https://code.tutsplus.com/a-guide-to-the-wordpress-http-api-the-basics–wp-25125t

Known Issues

Some users have reported that their IFrames are stripped out of the post content.
Requests for better performance of larger transfers and tranfers of images
Review of behavior when it re-imports, partiularly are the counts correct
Review using get_posts or get_comments with the appropriate parameters to get the counts and exists instead of using SQL
Incorrect notice, PHP Notice: The data could not be converted to UTF-8. You MUST have either the iconv or mbstring extension installed. This occurs even when Iconv is installed, could be related to Blogger reporting 0 comments
When the importer is running it’s not possible to stop it using the stop button
Blogger’s count of comments include those not linked to a post e.g. the post has been deleted.

Filters and Actions

These actions and filters have been added so that you can extend the functionality of the importer without needing to modify the code.

Action – import_start – This is run when the import starts processing the records for a new blog

Action – import_done – This is run when the import finishes processing the records for a blog.

Filter – blogger_importer_congrats – Passes the list of options shown to the user when the blog is complete, options can be added or removed.

Installation

Upload the blogger-importer folder to the /wp-content/plugins/ directory
Activate the plugin through the ‘Plugins’ menu in WordPress

Prerequisites

The importer connects your server to the blogger server to copy across the posts. For this to work you need to have connectivity from the server to the internet and also have at least one of the remote access protocols enabled, e.g. curl, streams or fsockopen. You can use the Core Control plugin to test if these are working correctly. The importer connects to Google over a secure connection so OpenSSL needs to be enabled on your server.
The importer uses the SimplePie classes to read and process the data from blogger so you will need the php-xml module installed on your webserver.

Preparation

It is strongly recommended that you disable all other plugins and caching during the import.

This will ensure that the information transfers across as smoothly as possible and that posts and comments are correctly transferrred.

How to use

On your Blogger account, visit the Settings->Other page, and locate the “Export Blog” option. This will download an XML file containing your posts and comments.
In WordPress, the Blogger Importer is available from the Tools->Import menu.
Upload the XML file to WordPress.
The posts will be read and you will be given the option to map the authors of the posts appropriately.
Allow the import to finish.
If the import fails halfway, you can simply retry. Already imported posts will be skipped and not duplicated.

Screenshots

FAQ

How do I re-import?

Simply upload the XML file again. Already imported posts will be skipped and not duplicated.

Once I’ve imported the posts do I need to keep the plugin?

No, you can remove the plugin once you’ve completed your migration.

How do I know which posts were imported?

Each of the posts loaded is tagged with a meta tags indicating where the posts were loaded from. The permalink will be set to the visible URL if the post was published or the internal ID if it was still a draft or scheduled post

blogger_author
blogger_blog
blogger_permalink

After importing there are a lot of categories

Blogger does not distinguish between tags and categories so you will likely want to review what was imported and then use the categories to tags converter

What about pages?

This importer does not handle blogger pages, you will need to manually transfer them.

What about images?

This version of the importer imports these too, but you can disable this via a setting in the blogger-importer.php file. Tracking images of size 1×1 are not processed. If you with to specifically exclude other images you could code something for the image_filter function.

What size are the images?

The importer will attempt to download the a large version of the file if one is available. This is controlled by the setting “LARGE_IMAGE_SIZE” and defaults to a width of 1024. The display size of the images is the “medium” size of images as defined on WordPress. You can change this in advance if you want to show a different size.

How do I know what images are skipped?

If you hover over the progress bar for images it will tell you how many images are skipped. To see the filenames of these images you will need to enable WordPress debugging to log to file. See https://wordpress.org/documentation/article/debugging-in-wordpress/

What about future posts?

The scheduled posts will be transferred and will be published as specified. However, Blogger and WordPress handle drafts differently, WordPress does not support dates on draft posts so you will need to use a plugin if you wish to plan your writing schedule.

Are the permalinks the same?

No, WordPress and Blogger handle the permalinks differently. However, it is possible to use the redirection plugin or your .htaccess file to map the old URLs across to the new URLs.

My posts and comments moved across but some things are stripped out

The importer uses the SimplePie classes to process the data, these in turn use a Simplepie_Sanitize class to remove potentially malicious code from the source data. If the php-xml module is not installed then this may result in your entire comment text being stripped out and the error “PHP Warning: DOMDocument not found, unable to use sanitizer” to appear in your logs.

The comments don’t have avatars

This is a known limitation of the data that is provided from Blogger. The WordPress system uses Gravatar to provide the images for the comment avatars. This relies the email of the person making the comment. Blogger does not provide the email address in the data feed so WordPress does not display the correct images. You can manually update or script change to the comment email addresses to work around this issue.

It does not seem to be processing the images

The most common reasons for this are lack of memory and timeouts, these should appear in your error log. Also check you’ve not run out of disk space on your server. Because WordPress stores the files in multiple resolutions one image might take up as much as 250kb spread across 5 files of different sizes.

How do I make the images bigger or smaller? / My images are fuzzy

The importer will attempt to download a large version of images but it displays them on the blog at the medium size. If you go into your settings->media options then you can display a different size “medium” image by default. You can’t make this bigger than the file that has been downloaded which is where the next setting comes in.

The default size for the large images is 1024, you can change this to an even larger size by changing the following line in the blogger-import.php file.

const LARGE_IMAGE_SIZE = ‘1024’;

The file downloaded won’t be bigger than the origional file so if it was only 800×600 to start with then it won’t be any bigger than that.

If your origional blog has hardcoded width and height values that are larger than the medium size settings then that might result in your images becoming fuzzy.

I’ve run out of disk space processing the images

The importer is designed to download the high resolution images where they are available. You can either disable the downloading of images or you can change the constant LARGE_IMAGE_SIZE string in the blogger-importer.php file to swap the links with a smaller image.

Changelog

0.9.2

Add support for WordPress 6.2

0.9.1

Add support for WordPress 6.1

0.9

Complete rewrite to use XML files instead.

0.8

Fixed issue with the authors form not showing a the list of authors for a blog
Simplified check for duplicate comments
Code simplified for get_authors and get_author_form
Fixed issue with wpdb prepare and integer keys by switching to a sub select query
Make comment handling more robust
Simplified functions to reduce messages in the log

0.7

Fixed issue with drafts not being imported in the right state
Added extra error handling for get_oauth_link to stop blank tokens being sent to the form
Restructured code to keep similar steps in single function and to allow testing of components to be done
Re-incorporated the “congrats” function and provided a sensible list of what to do next
Add a geo_public flag to posts with geotags
Dropped _normalize_tag after confirming that it’s handled by SimplePie
Added image handling https://core.trac.wordpress.org/ticket/4010
Added setting author on images
Added error handling in get_oauth_link() as suggested by daniel_henrique ref https://core.trac.wordpress.org/ticket/21163
Added a check for OpenSSL as suggested by digitalsensus
Fixed issue with SimplePie santizer not getting set in WordPress 3.5
Added filter for the congrats function ‘blogger_importer_congrats’ so other plugins can add in new options
Converted manual HTML table to WP_LIST_TABLE
Moved inline Javascript to separate file to aid debugging and testing
Wrapped data sent to Javascript in I18n functions.
Fixed timeout error in the Javascript, timeouts were not being used.
Supress post revisions when importing so that DB does not grow
Added processing of internal links
Added uninstall.php to remove options on uninstall
Added a timeout value to all of the wp_remote_get calls as people have reported timeout issues
Added a setting to control the large images downloaded from blogger.
Stopped logging all the post and comment IDs in arrays and storing in option this improved the importing of very large blogs
Fixed issue with comment_author_IP notice
Code restructuring to use classes for blog objects
Changed AJAX calls to use technique described here https://codex.wordpress.org/AJAX_in_Plugins#Ajax_on_the_Administration_Side
Added AdminURL to the greet function rather than hardcoded path
Defaulted to turn off post pingbacks
Fix to stop it counting pingbacks, issue reported by realdoublebee
Retrofitted Security enhancement from 0.6, nonce added to form buttons on main screen
Security enhancement, nonce added to form button on authors screen
Updated POT file
Greek Translation from Stergatou Eleni https://buddypress.org/community/members/lenasterg/

0.6

Security enhancement, nonce added to form button on main screen

0.5

Merged in fix by SergeyBiryukov https://core.trac.wordpress.org/ticket/16012
Merged in rmccue change to get_total_results to also use SimplePie from https://core.trac.wordpress.org/attachment/ticket/7652/7652-blogger.diff
Reviewed in rmccue’s changes in https://core.trac.wordpress.org/attachment/ticket/7652/7652-separate.diff issues with date handling functions so skipped those
Moved SimplePie functions in new class WP_SimplePie_Blog_Item incorporating get_draft_status and get_updated and convert date
Tested comments from source blog GMT-8, destination London (currently GMT-1), comment dates transferred correctly.
Fixed typo in oauth_get
Added screen_icon() to all pages
Added GeoTags as per spec on https://codex.wordpress.org/Geodata
Change by Otto42, rmccue to use Simplepie XML processing rather than Atomparser, https://core.trac.wordpress.org/ticket/14525 ref: https://core.trac.wordpress.org/attachment/ticket/7652/7652-blogger.diff
this also fixes https://core.trac.wordpress.org/ticket/15560
Change by Otto42 to use OAuth rather than AuthSub authentication, should make authentication more reliable
Fix by Andy from Workshopshed to load comments and nested comments correctly
Fix by Andy from Workshopshed to correctly pass the blogger start-index and max-results parameters to oAuth functions and to process more than one batch https://core.trac.wordpress.org/ticket/19096
Fix by Andy from Workshopshed error about incorrect enqueuing of scripts also changed styles to work the same
Change by Andy from Workshopshed testing in debug mode and wrapped ajax return into a function to suppress debug messages
Fix by Andy from Workshopshed notices for undefined variables.
Change by Andy from Workshopshed Added tooltip to results table to show numbers of posts and comments skipped (duplicates / missing key)
Fix by Andy from Workshopshed incorrectly checking for duplicates based on only the date and username, this gave false positives when large numbers of comments, particularly anonymous ones.

0.4

Fix for tracking images being added by Blogger to non-authenticated feeds https://core.trac.wordpress.org/ticket/17623

0.3

Bugfix for 403 Invalid AuthSub Token https://core.trac.wordpress.org/ticket/14629

0.1

Initial release