mirror of https://github.com/dapr/docs.git
* Tweaking the example to match what was demoed during the 9/21/2021 community call
* Added example CEL expressions * Added link to 9/21/2021 community call youtube video * Added section headers for the right nav
This commit is contained in:
Phil Kedy
parent
ccc6ebd819
commit
a927dd1028
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@ -42,14 +42,14 @@ metadata:
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name: myevent-subscription
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spec:
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pubsubname: pubsub
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topic: transactions
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topic: inventory
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routes:
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rules:
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- match: event.type == "withdraw.v3"
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path: /withdraw.v3
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- match: event.type == "withdraw.v2"
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path: /withdraw.v2
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default: /withdraw
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- match: event.type == "widget"
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path: /widgets
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- match: event.type == "gadget"
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path: /gadgets
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default: /products
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scopes:
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- app1
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- app2
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@ -77,24 +77,24 @@ def subscribe():
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subscriptions = [
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{
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'pubsubname': 'pubsub',
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'topic': 'transactions',
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'topic': 'inventory',
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'routes': {
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'rules': [
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{
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'match': 'event.type == "withdraw.v3"',
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'path': '/withdraw.v3'
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'match': 'event.type == "widget"',
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'path': '/widgets'
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},
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{
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'match': 'event.type == "withdraw.v2"',
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'path': '/withdraw.v2'
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'match': 'event.type == "gadget"',
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'path': '/gadgets'
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},
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],
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'default': '/withdraw'
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'default': '/products'
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}
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}]
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return jsonify(subscriptions)
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@app.route('/withdraw', methods=['POST'])
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@app.route('/products', methods=['POST'])
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def ds_subscriber():
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print(request.json, flush=True)
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return json.dumps({'success':True}), 200, {'ContentType':'application/json'}
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@ -113,30 +113,30 @@ app.use(bodyParser.json({ type: 'application/*+json' }));
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const port = 3000
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app.get('/dapr/subscribe', (req, res) => {
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res.json([
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{
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pubsubname: "pubsub",
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topic: "transactions",
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routes: {
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rules: [
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{
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match: 'event.type == "withdraw.v3"',
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path: '/withdraw.v3'
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},
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{
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match: 'event.type == "withdraw.v2"',
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path: '/withdraw.v2'
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},
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],
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default: '/withdraw'
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}
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}
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]);
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res.json([
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{
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pubsubname: "pubsub",
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topic: "inventory",
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routes: {
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rules: [
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{
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match: 'event.type == "widget"',
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path: '/widgets'
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},
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{
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match: 'event.type == "gadget"',
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path: '/gadgets'
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},
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],
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default: '/products'
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}
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}
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]);
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})
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app.post('/withdraw', (req, res) => {
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console.log(req.body);
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res.sendStatus(200);
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app.post('/products', (req, res) => {
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console.log(req.body);
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res.sendStatus(200);
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});
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app.listen(port, () => console.log(`consumer app listening on port ${port}!`))
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@ -145,25 +145,25 @@ app.listen(port, () => console.log(`consumer app listening on port ${port}!`))
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{{% codetab %}}
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```csharp
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[Topic("pubsub", "transactions", "event.type ==\"withdraw.v3\"", 1)]
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[HttpPost("withdraw.v3")]
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public async Task<ActionResult<Account>> WithdrawV3(TransactionV3 transaction, [FromServices] DaprClient daprClient)
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[Topic("pubsub", "inventory", "event.type ==\"widget\"", 1)]
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[HttpPost("widgets")]
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public async Task<ActionResult<Account>> HandleWidget(Widget transaction, [FromServices] DaprClient daprClient)
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{
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// Logic
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return account;
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}
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[Topic("pubsub", "transactions", "event.type ==\"withdraw.v2\"", 2)]
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[HttpPost("withdraw.v2")]
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public async Task<ActionResult<Account>> WithdrawV2(TransactionV2 transaction, [FromServices] DaprClient daprClient)
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[Topic("pubsub", "inventory", "event.type ==\"gadget\"", 2)]
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[HttpPost("gadgets")]
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public async Task<ActionResult<Account>> HandleGadget(Gadget transaction, [FromServices] DaprClient daprClient)
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{
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// Logic
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return account;
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}
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[Topic("pubsub", "transactions")]
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[HttpPost("withdraw")]
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public async Task<ActionResult<Account>> Withdraw(Transaction transaction, [FromServices] DaprClient daprClient)
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[Topic("pubsub", "inventory")]
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[HttpPost("products")]
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public async Task<ActionResult<Account>> HandleProduct(Product transaction, [FromServices] DaprClient daprClient)
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{
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// Logic
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return account;
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@ -208,19 +208,19 @@ func configureSubscribeHandler(w http.ResponseWriter, _ *http.Request) {
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t := []subscription{
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{
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PubsubName: "pubsub",
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Topic: "transactions",
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Topic: "inventory",
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Routes: routes{
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Rules: []rule{
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{
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Match: `event.type == "withdraw.v3"`,
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Path: "/withdraw.v3",
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Match: `event.type == "widget"`,
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Path: "/widgets",
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},
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{
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Match: `event.type == "withdraw.v2"`,
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Path: "/withdraw.v2",
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Match: `event.type == "gadget"`,
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Path: "/gadgets",
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},
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},
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Default: "/withdraw",
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Default: "/products",
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},
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},
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}
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@ -244,14 +244,14 @@ func main() {
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require_once __DIR__.'/vendor/autoload.php';
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$app = \Dapr\App::create(configure: fn(\DI\ContainerBuilder $builder) => $builder->addDefinitions(['dapr.subscriptions' => [
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new \Dapr\PubSub\Subscription(pubsubname: 'pubsub', topic: 'transactions', routes: (
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new \Dapr\PubSub\Subscription(pubsubname: 'pubsub', topic: 'inventory', routes: (
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rules: => [
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('match': 'event.type == "withdraw.v3"', path: '/withdraw.v3'),
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('match': 'event.type == "withdraw.v2"', path: '/withdraw.v2'),
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('match': 'event.type == "widget"', path: '/widgets'),
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('match': 'event.type == "gadget"', path: '/gadgets'),
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]
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default: '/withdraw')),
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default: '/products')),
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]]));
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$app->post('/withdraw', function(
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$app->post('/products', function(
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#[\Dapr\Attributes\FromBody]
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\Dapr\PubSub\CloudEvent $cloudEvent,
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\Psr\Log\LoggerInterface $logger
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@ -266,7 +266,34 @@ $app->start();
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{{< /tabs >}}
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In these examples, depending on the type of the event (`event.type`), the application will be called on `/withdraw.v3`, `/withdraw.v2` or `/withdraw`. The expressions are written as [Common Expression Language (CEL)](https://opensource.google/projects/cel) where `event` represents the cloud event. Any of the attributes from the [CloudEvents core specification](https://github.com/cloudevents/spec/blob/v1.0.1/spec.md#required-attributes) can be referenced in the expression.
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## Common Expression Language (CEL)
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In these examples, depending on the type of the event (`event.type`), the application will be called on `/widgets`, `/gadgets` or `/products`. The expressions are written as [Common Expression Language (CEL)](https://github.com/google/cel-spec) where `event` represents the cloud event. Any of the attributes from the [CloudEvents core specification](https://github.com/cloudevents/spec/blob/v1.0.1/spec.md#required-attributes) can be referenced in the expression.
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### Example expressions
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Match "important" messages
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```javascript
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has(event.data.important) && event.data.important == true
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```
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Match deposits greater than $10000
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```javascript
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event.type == "deposit" && event.data.amount > 10000
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```
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Match multiple versions of a message
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```javascript
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event.type == "mymessage.v1"
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```
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```javascript
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event.type == "mymessage.v2"
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```
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## CloudEvent attributes
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For reference, the following attributes are from the CloudEvents specification.
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@ -476,7 +503,13 @@ Currently, comparisons to time (e.g. before or after "now") are not supported.
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## Next steps
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- Try the [Pub/Sub quickstart sample](https://github.com/dapr/quickstarts/tree/master/pub-sub)
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Watch [this video](https://www.youtube.com/watch?v=QqJgRmbH82I&t=1063s) on how to use message routing with pub/sub.
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<p class="embed-responsive embed-responsive-16by9">
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<iframe width="688" height="430" src="https://www.youtube.com/embed/QqJgRmbH82I?start=1063" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
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</p>
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- Try the [Pub/Sub routing sample](https://github.com/dapr/samples/tree/master/pub-sub-routing)
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- Learn about [topic scoping]({{< ref pubsub-scopes.md >}})
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- Learn about [message time-to-live]({{< ref pubsub-message-ttl.md >}})
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- Learn [how to configure Pub/Sub components with multiple namespaces]({{< ref pubsub-namespaces.md >}})
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