# Firebase Authentication

###### tags: `olympus`

## User Management
[Firebase official docs](https://firebase.google.com/docs/auth/admin/manage-users#go)

### Official user struct fields
- Disabled `bool`
- DisplayName `string`
- Email `string`
- EmailVerified `bool`
- Password `string`
- PhoneNumber `string`
- PhotoURL `string`
- UID `string`

### Custom token
- Create a new mock user

user := (&auth.UserToCreate{}).
		Email("[e-mail]").
		EmailVerified(false).
		PhoneNumber("[phone]").
		Password("secretPassword").
		DisplayName("John Doe").
		PhotoURL("http://www.example.com/12345678/photo.png").
		Disabled(false)
record, err := a.CreateUser(ctx, user)

- Check this user

users, errs := a.ListUsers(ctx)
if len(errs) != 0 {
	log.Fatalf("Failed to list users: %#v", errs)
}
log.Infof("user: %#v", users[0])


---

- Token minting with claims

claim := map[string]interface{}{
	"policies": []string{
		"user.create",
		"user.update",
	},
}

tokenId := a.CreateCustomTokenWithClaims(ctx, users[0].UID, claim)
log.Infof("tokenId: %#v", tokenId)


---

- Website sign-in emulation
<details>
<summary>emulator</summary>

    package clients

    import (
        "bytes"
        "encoding/json"
        "fmt"
        "io/ioutil"
        "net/http"
    )

    const (
        verifyCustomTokenURL = "https://www.googleapis.com/identitytoolkit/v3/relyingparty/verifyCustomToken?key=%s"
    )

    func SignInWithCustomToken(token string) (string, error) {
        req, err := json.Marshal(map[string]interface{}{
            "token":             token,
            "returnSecureToken": true,
        })
        if err != nil {
            return "", err
        }


        // How to get the key?
        // https://developers.google.com/maps/documentation/places/web-service/get-api-key#gcloud-restrict
        apiKey := "AIzaSyAbCnHvR0cbTbH-E9cOpYGc9-q8aTAWD5M"

        resp, err := postRequest(fmt.Sprintf(verifyCustomTokenURL, apiKey), req)
        if err != nil {
            return "", err
        }

        var respBody struct {
            IDToken string `json:"idToken"`
        }

        if err := json.Unmarshal(resp, &respBody); err != nil {
            return "", err
        }

        return respBody.IDToken, err
    }

    func postRequest(url string, req []byte) ([]byte, error) {
        resp, err := http.Post(url, "application/json", bytes.NewBuffer(req))
        if err != nil {
            return nil, err
        }

        defer resp.Body.Close()
        if resp.StatusCode != http.StatusOK {
            return nil, fmt.Errorf("unexpected http status code: %d", resp.StatusCode)
        }
        return ioutil.ReadAll(resp.Body)
    }

</details>

token, err := clients.SignInWithCustomToken(tokenId)
if err != nil {
	log.Fatalf("Failed to sign in: %v", err)
}
log.Infof("token: %#v", token)


---

- Server side verify id token

aToken := a.VerifyIdToken(ctx, token)
log.Infof("aToken: %#v", aToken)


---

## Custom user claims