projections-nodejs

Client implementation in javascript for the projections service.

Installation

npm i @fraym/projections

GraphQL

You can access the graphQL api at http://projections:3000/delivery/graphql. There is a sandbox available at http://projections:3000/delivery/graphql/sandbox.

You need to add the Tenant-Id header in order to use the graphQL Endpoint and the sandbox.

Config

Use a .env file or env variables to configure cte clients and the command:

PROJECTIONS_SERVER_ADDRESS=127.0.0.1:9000

Env variable placeholders in migrations

You can use placeholders that match environment variables in argument strings in your schema definitions:

In the following example the {{env.BACKEND_HOSTNAME}} part will be replaced by the value of the BACKEND_HOSTNAME environment variable. Please add your used env variables to the .env file that is used to configure the migration command.

type TestType {
    value: String
        @webhook(
            url: "http://{{env.BACKEND_HOSTNAME}}/event-organizing/contingent/projections/frontend/contingent-management/webhook"
            method: "GET"
            header: [{ key: "Content-Type", value: "'application/json'" }]
            body: [
                { key: "metadata", value: "metadata" }
                { key: "payload", value: "payload" }
                { key: "projection", value: "projection" }
            ]
        )
}

Usage

Create the client

const deliveryClient = await newDeliveryClient();

Authorization

All delivery client functions make use of the AuthData object. This data is used to check access for the desired action.

You can add the FRAYM_AUTH_OWNER scope in case you are performing an action that is no subject to restrictions.

Fields:

• tenantId: Id of the tenant to use
• scopes: Slice of scopes to use for the action
• data: Data that is used in directives like @filterFromJwtData

Event Metadata

You can specify the correlation and causation IDs for the upsert and delete functions. The eventMetadata parameter is optional for all these functions and has the following structure:

const eventMetadata = {
    correlationId: "some-correlation-id",
    causationId: "some-causation-id",
};

Upsert data in projection

In general you upsert data by publishing events on the event stream. There are cases where you want to improve performance and get detailed validation output. In these cases you can use the client to directly upsert data. Do not worry, this is still event based under the hood.

const response = await client.upsertData<{ fieldName: string }>(
    "ProjectionName",
    authData,
    "dataId",
    {
        fieldName: "value",
    },
    eventMetadata
);

The response contains the following fields:

In case of no validation errors:

• data: The new data after your upsert action

In case of validation errors:

• validationErrors: List of global validation errors that are not related to a single field
• fieldValidationErrors: Validation errors mapped by the name of the field that they relate to

Delete data from projection

In general you delete data by publishing events on the event stream. There are cases where you want to improve performance and get detailed validation output. In these cases you can use the client to directly delete data. Do not worry, this is still event based under the hood.

Delete by Id:

const numberOfDeletedEntries = await client.deleteDataById("ProjectionName", authData, "dataId", eventMetadata)

Delete by filter:

const numberOfDeletedEntries = client.deleteDataByFilter("ProjectionName", authData, filter, eventMetadata)

Get a single projection element

A filter could look like this:

const filter := {
	fields: {
        fieldName: {
            operation: "equals",
            type: "Int",
            value: 123,
        },
    },
}

The name of YourProjection has to equal your projection name in your schema (also in casing). The id has to match the id of the projection element that you want to get.

const data = await deliveryClient.getData(
    "YourProjection",
    authData,
    "id",
    filter,
    returnEmptyDataIfNotFound
);

Get (paginated / filtered / ordered) data

The name of YourProjection has to equal your type name in your schema (also in casing).

No pagination:

const dataList = await deliveryClient.getDataList("YourProjection", authData);

The dataList response contains the following fields:

• limit: The pagination limit
• page: The pagination page
• total: The total amount of elements matching the given filter
• data: The selected data

With pagination:

const limit = 50; // elements to query per page
const page = 1; // number of the page you want to select, first page starts at: 1
const dataList = await deliveryClient.getDataList("YourProjection", authData, limit, page);

With filter:

const dataList = await deliveryClient.getDataList(
    "YourProjection",
    authData,
    undefined,
    undefined,
    {
        fields: {
            fieldName: {
                operation: "equals",
                type: "Int",
                value: 123,
            },
        },
    }
);

All Filters are evaluated by:

• checking that all field filters match
• checking that all and filters match
• checking that one of the or filters match

Avaliable types:

• String
• ID
• DateTime
• Int
• Float
• Boolean

Avaliable operators for all types:

• equals
• notEquals

Avaliable options for the filter type DateTime:

• inArray
• notInArray
• after
• before

Avaliable options for the filter type String and ID:

• inArray
• notInArray

Avaliable options for the filter type Int and Float:

• lessThan
• greaterThan
• lessThanOrEqual
• greaterThanOrEqual

With order:

All order definitions are prioritized in the order that they are defined (the first definition is prioritized over the second).

const dataList = await client.getDataList(
    "YourProjection",
    authData,
    undefined,
    undefined,
    undefined,
    [
        {
            field: "fieldName",
            descending: true, // omit this value for asc order
        },
    ]
);

Gracefully close the delivery client

You won't lose any data if you don't. Use it for your peace of mind.

client.close();