Implementing the Gmail Application Handler

[ra-jeev]

Description

Please include a summary of the change and the issue it solves.

Fixes #5364

Type of change

• ⚡ New feature (non-breaking change which adds functionality)
• 📄 This change requires a documentation update

What is the solution?

Implemented the Gmail Application Handler using the Gmail API with the help of google-api-python-client and google-auth-oauthlib libraries. The integration supports pulling emails from the OAuth authenticated user's Gmail mailbox using the filter queries supported by Gmail. It then extracts the text and other relevant details from the individual emails and add it to the database. It also supports sending text emails to the destination email address by using the Insert command. It also supports creating threads in case of replying to emails.

Checklist:

• My code follows the style guidelines(PEP 8) of MindsDB.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation, or created issues to update them.
• I fixed|updated|added unit tests and integration tests for each feature (if applicable).
• I have shared a short loom video or screenshots demonstrating any new functionality.

[ra-jeev]

I have read the CLA Document and I hereby sign the CLA

-- rajeev

[tmichaeldb]

Thanks for the Pull Request! Main changes I'd like to see before merging:

• Add basic tests
• Add example for SELECT row in docs

[ra-jeev]

Thanks a lot @tmichaeldb for reviewing the PR. I'll mostly be making the requested changes today.

Should I change the column name "from" to something else (say sender) to avoid clashes with SQL reserved keywords?

Thanks,
Rajeev

[ra-jeev]

The Checks are failing because of torch. What should be done here?

ERROR: Could not find a version that satisfies the requirement torch<2.1,>=2.0.0 (from lightwood) (from versions: 1.0.0, 1.0.1, 1.0.1.post2, 1.1.0, 1.2.0, 1.3.0, 1.3.1, 1.4.0, 1.5.0, 1.5.1, 1.6.0, 1.7.0, 1.7.1, 1.8.0, 1.8.1, 1.9.0, 1.9.1, 1.10.0, 1.10.1, 1.10.2, 1.11.0, 1.12.0, 1.12.1, 1.13.0, 1.13.1)
ERROR: No matching distribution found for torch<2.1,>=2.0.0

[tmichaeldb]

LGTM. Please don't merge yet though due to figuring out how to combine this PR with #5890 .

[ZoranPandovski]

Amazing, @ra-jeev , @maarioos1308 is this ready?

[ra-jeev]

Amazing, @ra-jeev , @maarioos1308 is this ready?

Hey @ZoranPandovski, I think it should be ready by tomorrow. (@maarioos1308 added attachments parsing today).

Also,
In our testing we found that the text extracted from 'text/html' is almost the same which Gmail returns in the 'text/plain' part (Gmail automatically creates a text version of the HTML). So, does it make sense to have a separate column for storing the text extracted from html?

IMO, it was duplicate content so I had not added it in my PR, but @maarioos1308 had it.

[ra-jeev]

Hey @ZoranPandovski & @tmichaeldb,
This PR is complete for initial merge from our end. Main changes compared to the approved PR

1. Support for taking credentials file from S3 (the default) with a fallback to the local file
2. A couple of new columns and support for storing attachments details
3. Corresponding changes in the README file + more examples

Things to note

1. We haven't added HTML parsing as the text extracted from HTML is almost the same as what we get from 'plain/text' (which Gmail automatically generates)
2. For attachments, we're just storing their meta details in a column and not downloading + extracting texts from them.

Both of these can be added if you think we need to have it. But for downloads I've a concern for the attachments size.

Once this PR is merged we can close #5890. Then I can do one more change related to creating email drafts which is not supported yet.

Thanks,
Rajeev & Marios(@maarioos1308)

[ZoranPandovski]

Excellent, thanks, team, and congratulations on winning the first prize :trophy: . Please feel free to open an issue for all of the new features :raised_hands:

[ra-jeev]

Thanks a lot @ZoranPandovski :-)