firestruct

firestruct

This package flattens and unmarshals protojson encoded Firestore documents contained in Cloud Events into a native Go map[string]interface{} or struct (without Firestore protojson tags)

The package is ideal for cloud functions that are triggered by Cloud Events when you need simplified and easy to use Go data structures.

Why Should You Use It

Firestore Cloud Events wrap document fields in protojson type descriptor tags that are difficult to parse in Go. This package simplifies Firestore data by unwrapping documents into a type safe map or struct.

It allows you to re-use the native Go models used to create Firestore documents to also handle incoming cloud events, which in turn simplifies data processing or validation by other Go functions.

Example Usage

See the examples folder for all examples.

import (
    "github.com/bennovw/firestruct"
)

func MyCloudFunction(ctx context.Context, e event.Event) error {
    cloudEvent := firestruct.FirestoreCloudEvent{}
    err := json.Unmarshal(e.DataEncoded, &cloudEvent)
    if err != nil {
        fmt.Printf("Error unmarshalling firestore cloud event: %s", err)
        return err
    }

    // Extract and unwrap a protojson encoded Firestore document from a Cloud Event
    // Outputs a flattened map[string]interface{} without Firestore protojson tags
    m, err := cloudEvent.ToMap()
    if err != nil {
        fmt.Printf("Error converting firestore document to map: %s", err)
    }

    // Unwrap and unmarshal a protojson encoded Firestore document into a struct
    x := MyStruct{}
    err = cloudEvent.DataTo(&x)
    if err != nil {
        fmt.Printf("Error converting firestore document to MyStruct: %s", err)
        return err
    }

    return nil
}

// Supports all Firestore data types, including nested maps and arrays,
// Firestore struct tags are optional
type MyStruct struct {
    SomeTime   time.Time      `firestore:"timeData"`
    Title      string         `firestore:"stringData"`
    ID         uuid.UUID      `firestore:"uuidData"`
    IsWild     bool           `firestore:"boolData"`
    Age        int64          `firestore:"intData"`
    Weight     float64        `firestore:"doubleData"`
    Bytes      []byte         `firestore:"bytesData"`
    WildNull   any            `firestore:"nilData"`
    Place      latlng.LatLng  `firestore:"geoPointData"`
    NestedData map[string]any `firestore:"nestedMapData"`
}

Advanced Example

The package also provides two stand-alone functions to flatten a subset of Firestore data into a map[string]interface{} or unmarshal data directly into a struct without having to rely on type assertions or json.Marshal followed by json.Unmarshal

import (
    "github.com/bennovw/firestruct"
)

func MyCloudFunction(ctx context.Context, e event.Event) error {
    cloudEvent := firestruct.FirestoreCloudEvent{}
    err := json.Unmarshal(e.DataEncoded, &cloudEvent)
    if err != nil {
        fmt.Printf("Error unmarshalling firestore cloud event: %s", err)
        return err
    }

    // Unwraps a protojson encoded Firestore document, outputs a flattened map[string]interface{}
    uf, err := firestruct.UnwrapFirestoreFields(cloudEvent.Value.Fields)
    if err != nil {
        fmt.Printf("Error unwrapping firestore data: %s", err)
    }

    // Unmarshals a map[string]interface{} directly into a struct
    st := MyStruct{}
    err = firestruct.DataTo(&st, uf)
    if err != nil {
        fmt.Printf("Error populating MyStruct: %s", err)
    }

    return nil
}

License