**Disclaimer:** This is a free and open source project, but it relies on third-party web-services for some functions to work. This project is not affiliated with any third-party entities in any other sense.


# Yet Another Call Blocker

The goal of this project is to provide a free and open source application that can block unwanted calls or warn about probable intentions of the callers using a third-party crowdsourced phone number database (from some other proprietary app).


## How to use

* Install and launch the app.
* At first start, the app will suggest to download main database. Simply confirm the download and wait for a few seconds.  
  The DB will be downloaded from [another gitlab repo](https://gitlab.com/xynngh/YetAnotherCallBlocker_data).
* The option to show notifications for incoming calls is enabled by default, so the app will ask for a phone-related permission.  
  Grant the permission if you want to be able to use most of the app's features.
* After that you should be able to see recent calls with some additional info on the main screen of the app.  
  The app will also display notifications with some caller info during incoming calls.  
  You can press such a notification to see more info or to load detailed online reviews.
* Check the "Auto-update database" checkbox in menu (recommended) to automatically receive daily DB updates (these are delta updates, so they consume very little traffic).
* Check the "Block unwanted calls" checkbox if you want to enable automatic call blocking.
* You can also check the "Use contacts" checkbox if you want your contacts not to be treated as unknown callers.
* After these steps everything should just work. Enjoy!


## Features

At this point most of the essential features (one would expect from a call blocking app) are implemented. Here's an overview:

* Showing a notification with some caller info (positive/negative rating, category, number of negative reviews and such) when the phone's ringing. *Works offline.*
* Loading and displaying a list of reviews for a number (accessed from the notification or the info view). *Requires internet.*
* Automatic blocking of unwanted calls (may not work on some devices; tested to work on modern Android versions (including Android 10)). *Works offline.*
* Automatic update of the database (for offline use). *Requires internet.*
* Displaying a list of recent calls with caller rating and the ability to show more info or load online reviews for the number. The list *works offline*, but loading reviews *requires internet.*
* If "use contacts" option is enabled, the numbers present in the phone book are never blocked and the contact name is displayed next to/instead of a number throughout the app.


## Privacy

Protecting the user's privacy is the first concern during development. No personal data is sent to or otherwise shared with anyone.
The only known possible data leaks are the following:

* Database update procedure leaks user's IP address to the update servers.  
  The request also includes current database version (base or updated).
* Online review requests leak user's IP address coupled with the phone number in question.  
  Shouldn't be a big deal unless you call it for a bunch of numbers in your phone book.  
  If the "use contacts" feature is enabled, a confirmation dialog is shown if online reviews are requested for a number present in your phone book.

No other identifiable information is sent with the requests.


## Available data

The following data is available in the main offline database:

* a phone number,
* a category (telemarketers, dept collectors, scam, etc.),
* a number of negative reviews,
* a number of positive reviews,
* a number of neutral reviews.

The main database may receive delta updates from third-party servers.

The "featured" database provides "names" (company names or short descriptions) for some (presumably) subset of numbers in the main database.

The third-party servers can be queried for a list of detailed user reviews for a specific phone number.
A detailed review contains:

* A rating: positive, negative or neutral.
* A category: each review may have a different one.
* A title and a comment: the actual description the user left for the number.


## Rationale

Some may find the original application (whose DB and servers are used) hard to trust because of its proprietary nature (and also the use of firebase analytics and the like).  
But since the database behind that application is crowdsourced, some may find it acceptable (in a moral sense) to use that database in a separate open source application.  
Also, this project is meant to be non-commercial. So, there's that.


## License

[AGPLv3](https://www.gnu.org/licenses/agpl-3.0.en.html).  


## Contributing

Any contributions are very welcome.


## Building

Clone the project repo:

```
git clone https://gitlab.com/xynngh/YetAnotherCallBlocker.git
```

Clone the assets repo (optional step: allows to avoid the initial DB downloading after installation):

```
git clone https://gitlab.com/xynngh/YetAnotherCallBlocker_data.git
```

Sym-link the assets:

Linux
```
cd YetAnotherCallBlocker/app/src/main/assets/
ln -s ../../../../../YetAnotherCallBlocker_data/assets/sia .
```
Windows
```
cd YetAnotherCallBlocker\app\src\main\assets
mklink /d sia ..\..\..\..\..\YetAnotherCallBlocker_data\assets\sia
```

**or** copy the whole directory `YetAnotherCallBlocker_data/assets/sia` into `YetAnotherCallBlocker/app/src/main/assets/`.

Then you can build the app using Android Studio or using Gradle:

```
./gradlew assemble
```