django-tastypie-specific-fields

A tastypie extension that allows you to specify the fields you are interested in.

Django tastypie specific fields is a light and simple, but very usefull extension for django-tastypie. It allows you to get from a resource only the fields and/or related resources you are interested in. It is so flexible that you can make very specific requests lookup by specifying the fields you want at a very deep level in relatedness hierarchy starting from the main resource.

For example let us consider the publisher model (found in the example given with the project) which has id, prefix, title and website as fields. The response for the following request GET http://path/to/my/app/api/v1/publisher/?**fields=title,website**&format=json will be

{
    meta: {
        ...
    },
    objects: [
        {
            title: "Publisher1",
            website: "http://www.publisher1.com"
        },
        {
            title: "Publisher2",
            website: "http://www.publisher2.com"
        },
        ...
    ]
}

while the one for the "normal" request GET http://path/to/my/app/api/v1/publisher/?format=json will be

{
    meta: {
        ...
    },
    objects: [
        {
            id: 1,
            prefix: "pub1",
            title: "Publisher1",
            website: "http://www.publisher1.com"
        },
        {
            id: 2,
            prefix: "pub2",
            title: "Publisher2",
            website: "http://www.publisher2.com"
        },
        ...
    ]
}

---

Django-tastypie-specific-fields also supports relative fields filtering.

Let us consider the case where you have an author model with profession and birthdate as direct fields. This author is also related to a django user. If you just want to have for an author his profession, the first_name, the last_name and the id of the related django user, you can do the following very precise request GET http://path/to/my/app/api/v1/author/?**fields=profession,user(id,first_name,last_name)**&format=json which will give you the following response

{
    meta: {
        ...
    },
    objects: [
        {
            profession: "profession2",
            user: {
                first_name: "user2",
                id: 3,
                last_name: "user2"
            }
        },
        {
            profession: "profession3",
            user: {
                first_name: "user3",
                id: 4,
                last_name: "user3"
            }
        },
        ...
    ]
}

If you don't specify in parentheses any field of the related resource, it will give you back the whole related resource. GET http://path/to/my/app/api/v1/author/?**fields=profession,user**&format=json

{
    meta: {
    ...
    },
    objects: [
        {
            profession: "profession2",
            user: {
                date_joined: "2016-09-27T13:11:05.165000",
                email: "user2@mysite.com",
                first_name: "user2",
                id: 3,
                last_login: "2016-09-27T13:11:05.165000",
                last_name: "user2",
                username: "user2"
            }
        },
        {
            profession: "profession3",
            user: {
                date_joined: "2016-09-27T13:11:05.438000",
                email: "user3@mysite.com",
                first_name: "user3",
                id: 4,
                last_login: "2016-09-27T13:11:05.438000",
                last_name: "user3",
                username: "user3"
            }
        },
        ...
    ]
}

Django-tastypie-specific-fields also have a very good support of m2m(ManyToMany) relations

If you specify some fields to retreive from a m2m related resources, you will be given back the set of those related resources. But each element of this set will contain only the fields you need. In our example, a book can have many authors and also many genres. Here is the response for the GET http://path/to/my/app/api/v1/book/?**fields=title,genres(title),authors(profession,user)**&format=json request.

{
    meta: {
        ...
    },
    objects: [
        {
        authors: [
            {
                profession: "profession3",
                user: {
                    date_joined: "2016-09-27T13:11:05.438000",
                    email: "user3@mysite.com",
                    first_name: "user3",
                    id: 4,
                    last_login: "2016-09-27T13:11:05.438000",
                    last_name: "user3",
                    username: "user3"
                }
            },
            {
                profession: "profession2",
                user: {
                    date_joined: "2016-09-27T13:11:05.650000",
                    email: "user4@mysite.com",
                    first_name: "user4",
                    id: 5,
                    last_login: "2016-09-27T13:11:05.650000",
                    last_name: "user4",
                    username: "user4"
                }
            }
        ],
        genres: [
            {
                title: "genre1"
            },
            {
                title: "genre2"
            },
            {
                title: "genre3"
            }
            ],
                title: "Book 1"
            },
        ]
        ...
    ]
}

Advanced related resource fields lookup

Django-tastypie-specific-fields implements a recursive lookup process to get the specific fields you need. For this reason, you can specify the fields you want from a resource that is related to a related one, and so on. This simply means that you are allowed to do requests like the following:

path/to/my/app/api/v1/resource/?fields=field1,resource1(field11,resource12(resource21(field31,field32))

However, this will not work with ManyToMany relations

Acknowledgements

Thanks to:

• Florentin Jiechieu
• Hubert Noyessie
• Franklin Mbouopda