Pro Ember Data: Getting Ember Data to Work with Your API - podcast episode cover

Pro Ember Data: Getting Ember Data to Work with Your API

Jan 19, 202621 min
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Episode description

Focuses on effectively integrating Ember Data with various API structures. The text covers Ember Data's core architecture, including the store, adapters, and serializers, and explains their roles in data access, caching, and formatting. Readers will learn about different built-in adapters and serializers like RESTAdapter, JSONAPIAdapter, JSONSerializer, and RESTSerializer, understanding their expected API payload formats. A significant portion of the material is dedicated to customizing adapters and serializers to accommodate non-standard API conventions, handling nested data, and managing error responses. The book also details testing strategies for adapters and serializers and explores advanced topics such as consuming external APIs like Reddit and implementing polymorphic relationships, making it a valuable resource for developers looking to master Ember Data.

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Transcript

Speaker 1

Welcome back to the deep died curious minds. You know that feeling you've got this really powerful tool, maybe like a brand new engine, but your current setup, your infrastructure, maybe uses a slightly different kind of fuel. It doesn't quite mesh. Well, today we're tackling exactly that kind of challenge. But in the world of web development, specifically with mber Data. It's the data layer for mber dotjs apps and well, it's designed to make interacting with APIs and managing your

data really smooth, supercharge that user experience, you know. But here's the kicker. What if your API isn't shall we say standard, What if it uses different naming or weird URL structures or throws errors you don't expect. That's what we're digging into today. How mber data is a really smart design actually lets you adapt to any API out there.

Think of it like getting a universal translator. Yeah, making your app and your back end speak the same language, no matter how quirky that back end might be.

Speaker 2

Exactly that's a challenge a lot of developers face, right, integrating a really robust front end like ember data with an excus sting back end API that might be well, let's call it unique. Ember Data definitely has its own opinionated way of doing things, it's preferred conventions. But its real power, I think, is in how extensible it is. We're going to look at its core parts, the store, the adapters, and the serializers and see how understanding those

lets you connect to pretty much any data source. It really saves you from reinventing the wheel for common stuff like identity mapping or managing relationships.

Speaker 3

Okay, let's unpack that. An analogy might help imagine. Your app. Is this like bustling city and all your data users products whatever they're the citizens moving around. Mber Data is like the city management system, keeping track of everything, and at its heart there are these three key departments running the show. First up, you mentioned the store. What's that like city hall?

Speaker 2

Sort of? Yeah, think of the store as the city's central records office, but also like a super fast memory bank. When your application needs some data, it doesn't go straight to the API. It asks the store first.

Speaker 3

Ah, so it checks its cap precisely, and when data comes in, the store caches it intelligently. But it's more than just a simple cash The really clever part is the identity map. This prevents you from having say two different JavaScript objects representing the exact same user record and memory. How does that work? Well, imagine you fetch a list of contacts, maybe GD contacts, and later you fetch a

specific one GD contacts one. If contact one was in both responses, the store ensures you only ever have one object instance for that contact with EED one. It preserves that object identity.

Speaker 2

Okay, I see, so no confusing duplicates floating around. That sounds vital for keeping things consistent, especially in complex apps.

Speaker 3

Absolutely crucial for scalability and uh just general sanity. Really.

Speaker 2

So, the store holds the records, keeps them unique. But how does it actually, you know, talk to the outside world, to our potentially quirky API.

Speaker 3

Right, The store doesn't talk directly. It delegates. That's the job of the adapter.

Speaker 2

The adapter. Okay, so if the store City Hall, the adapter is the Department of Foreign Affairs. Huh yeah, that's a good way to put it. The adapter handles how to communicate with external data sources your API. Its job is to figure out the full URL for a request, actually make the HTTP call using ajax, fetch maybe even web sockets, and it can even talk to things that aren't remote APIs like the browser's local storage or index dB possible very and the key thing is this separation.

If your API changes how it expects requests, maybe moves from rest to grah ql, or just changes its URL scheme, often you only need to update the adapter, not rewrite huge chunks of your application logic decoupling nice exactly. Ember Data ships with a few standard ones REST adapter for common rest stuff JSON APA adapter, which is the default and follows the Jason Dot API spec and there used to be an active model adapter for rails though that's an add on now.

Speaker 3

Okay, So the adaptor handles the where and how of the request the transport layer basically, But what about the actual data the payload? What if the app I sends back data that looks completely different from what mber data expects, different grammar, different vocabulary.

Speaker 2

That, my friend, is where the serializer steps in.

Speaker 3

The serializer the linguist.

Speaker 2

Precisely, The serializer is your data's translator. It has two main jobs. First, serialization, taking data from your Mber app and formatting it correctly to send to the server. Second, normalization, taking the raw data received from the server and translating it into a structure. Mber Data understands, so.

Speaker 3

Adapter handles the connection. Serializer handles the language you got it.

Speaker 2

That separation is fundamental to ember Data's adaptability. It lets you tackle the how to talk and the what to say independently and.

Speaker 3

I'm guessing just like adapters, there are different serializers for different API languages.

Speaker 2

Spot on, mber Data gives you three main ones out of the box. There's the basic Jason serializer for simple flat Jason good starting points sometimes, and the rest serializer. This one expects data wrapped in a root key like contact, and it also understands how to handle sideloading.

Speaker 3

Sideloading what's that?

Speaker 2

Oh, that's when an API includes related data in the same response to save extra network requests like getting a contact and their company details all at once. The rest serializer can unpack.

Speaker 3

That gotcha, reduces chattiness exactly.

Speaker 2

And finally, there's the Jason up a serializer, which is built specifically for APIs that strictly follow the official Jason dot API specification. That's often the default. The idea is you pick the built in serializer that's closest to what your API does, and that minimizes the custom transation work you need to do initially.

Speaker 3

Okay, this is where it gets really practical for you listening, because let's face it, real world APIs aren't always textbook perfect are they? Rarely ember data anticipates this. That's why these customization hooks exist. It's about making your app talk smoothly to your specific back end warts and all. Let's start with customizing adapters. Say my API uses singular nouns for URLs like contact one instead of contacts one. How do I tell data?

Speaker 2

Yeah, that's a common one. It's surprisingly easy. You just override a method called pathsfotype in the adapter for that specific model. So in your app adapters contact dot js file, you'd add a path four type model name function and just make it return the singular model name. Done. Simple enough,

so that handles the base path. But what if I need a totally custom URL structure for a specific query, like searching contacts by city, but the API wants app contacts by city Los Angeles instead of a query peram like dot city los Angeles.

Speaker 3

Right, for specific query logic, you'd override are all four query. Again, probably in your contact adapter. That method gets the queer parameters and the model name, so you have everything you need to build that custom URL string like app contacts by cityquery dot city and yeah, you might need to remember to dasherize the city name turn los Angeles into los Angeles, which is pretty standard for URLs.

Speaker 2

Okay, that makes sense. You get full control over the URL generation for different actions. And thinking about, say using an external API like reddits. Their API for subreddit posts is something like reddit dot com. Rememberjs dot Jason, we'd use exactly that role for query override in a post adapter to hit that specific nonstandard URL.

Speaker 4

Right.

Speaker 2

Absolutely. That's a perfect example of adapting to a completely external, maybe slightly unusual API structure using the adapter hooks. And while we're talking adapters, there's more fine grain control too. You can influence how ember data decides whether to refetch data that's already in the store, methods like should background reload all or should background reload record. Let you return true or false to control background updates.

Speaker 3

So you can fine tune the caching behavior prevent unnecessary requests, but still keep data fresh.

Speaker 2

Precisely, maybe for certain data you always want the latest, so you force a reload for other less critical data. The cased version is fine for longer.

Speaker 3

Very cool. Okay, let's switch gears to serializers. The translators. APIs love different naming conventions, don't they snake case like first name, title case CamelCase. Our JavaScript usually prefers CamelCase. How do we bridge that gap without making our model ugly?

Speaker 2

Oh yeah, the casing battle. Mber data has elegant solutions for this. For just one or two specific fields, you can use the actress hash in your serializer. You map the model's camel case name to the API's key like first name.

Speaker 3

Oh, first name okay for isolated cases.

Speaker 2

But if your entile API uses, say, snake case, doing that for every attribute would be tedious. So instead you override a method called key for attribute in your main application serializer. This function receives the camel case attribute name from your model, and you just return the transformed snakecase version. Ember data then uses this for all attributes.

Speaker 3

Automatically, nice like setting a global.

Speaker 2

Rule exactly and again. Back to that Reddit example. Reddit uses snake case for things like numb comments. Right, So overwriting key for attribute lets our mber model use a clean numb comments while the serializer handles translating it to numb comments when talking to the Reddit API keeps the front end cord nice and idiomatic.

Speaker 3

Love it. What about relationships? APIs often just give you a foreign key like companied. How do we link that to a proper belongs to company relationship?

Speaker 2

In Ember another common pattern, you can override key for relationship in your serializer, similar to key for attribute. This method lets you tell ember Data how relationship keys are represented in the payload. You could tell it to expect ad appended to the relationship name. For instance, so company becomes companied, so.

Speaker 3

It automates linking company to the company relationship. Yeap.

Speaker 2

And one more quick one, what if your API doesn't use e'd as the primary key, maybe uses eed or SSN or something else. Just set the primary key property on your serializer to whatever the API uses like primary key ad. Mber Data will then know how to uniquely identify your records.

Speaker 3

Okay, handling keys casing relationships. That covers a lot of common API quirks. Yeah, but what if the whole structure of the response is just different, not just the keys, but the nesting, the wrapping, Like that Reddit example where the good stuff is buried deep.

Speaker 2

Now we're talking normalization. This is the serializer's superpower for reshaping incoming data. Let's say your API wraps everything in a generic data key like data Yeah, you're chosen. Serializer might not expect that wrapper, yes, so you override normalizer response. This method gets the raw payload straight from the adapter. Inside normalizer response, you can manipulate that payload. You could

say payload equal payload dot data to unwrap it. Then crucially you call super dot normalizer response store primary model class, payload, ID request type, passing the modified payload along. This lets the standard normalization process take over with data it now understands.

Speaker 3

Is there like preprocessing the raw response before Mberdata's main normalization engine.

Speaker 2

Sees it exactly, You're cleaning it up, reshaping it into the format your base serializer, like Jason serializer Arrest serializer expects. Remember ember Data's internal format it aims for is kind of like jason dot API, but with singular, dasherized types and camelcased attributes. Normalization bridges the gap between your API and that internal format.

Speaker 3

And for that Reddit example, with data nested under data dot children, not data, that's where normalized response or maybe a more specific one like normalized array response.

Speaker 2

Comes in precisely, you'd override the appropriate normalized method, dig into that nested structure, extract the array of actual post data, maybe do some transformation on each item, and then pass that cleaned up array to super makes sense.

Speaker 3

It lets you handle really arbitrarily structured APIs.

Speaker 2

It does, And normalized response actually delegates to more specific methods based on the type of request normalized final response, normalized find record response, normalized save response, etc. So you can target your normalization logic very precisely if needed.

Speaker 3

Super granular control. Now, when we send data back saving or updating, you mentioned something called a snapshot object. Why is that important?

Speaker 2

Ah, yes, the snapshot. When you save a record, the adapter doesn't get the live ember data record directly, it gets a snapshot. Think of the snapshot as a re only sort of frozen representation of the record's data at that specific moment in time.

Speaker 3

Okay, why not just use the live record.

Speaker 2

Because accessing properties on a live Ember data record can sometimes trigger side effects like automatically fetching unloaded relationships. You don't want that happening accidentally when you're just trying to package up data to send to the server. The snapshot provides a safe, stable copy of the data for the serializer to work with. Serialize into hash serialized methods. Use it without any unexpected side effects. It guarantees you're only sending the intended data.

Speaker 3

Got it. It's like a safe copy for serialization purposes, prevents unexpected data.

Speaker 2

Loading exactly keeps things predictable.

Speaker 3

Wow. Okay, that covers a ton of ground on adapting the core communication. But what about more complex data patterns like nested objects. What if my API sends back an address object right inside the contact payload?

Speaker 2

Good question. Mber data gives you a couple of options there. For simple read only nested objects, where the address doesn't really need to be its own manager, you can just declare the attribute without a specific type or transform like it at Bautry address. Mber data will just treat it as a plain JavaScript object and pass it through Simple.

Speaker 3

Okay for basic nested blobs of data.

Speaker 2

But if that nested object like the address, has its own ID and conceptually is a separate entity, you might want to manage your link to elsewhere. Then you can treat it as an embedded record. You use the embedded records mixin in your serializer. This tells the serializer to look for those nested objects and actually turn them into proper, fully fledged MBER data records, establishing the has many or belongs to relationship automatically, so.

Speaker 3

It extracts the nested AID one three street mood yeah and makes it a real address record linked.

Speaker 2

To the contact precisely. Like if you have skills AID one name, MBRA eighty two name texting embedded in a user payload, the mixin can turn those into actual skill records related to the user. One important caveat, though the embedded records mixin is designed primarily for the rest serializer or custom serializers, it doesn't really play nicely with the strict Jason a PI serializer.

Speaker 3

Okay, so if you're using strict Jason, that API embedding isn't the standard approach anyway, Right, you'd use relationship.

Speaker 2

Links exactly JSON that API prefers relationships defined by type addresses ED one twenty three in a relationships block rather than embedding the full address object directly under the contact.

Speaker 3

That makes sense. Use the tool that fits the standard you're working with.

Speaker 2

Right, Embedded records are powerful for certain API styles, but maybe not the JSON dot API way.

Speaker 3

Okay, moving on errors they happen. How does mber data help us handle API errors gracefully?

Speaker 2

It actually has pretty robust built in error handling. It maps common HTTP status codes to specific error objects. The most common one is probably four hundred and twenty two unprocessable entity. Mber data treats this as a validation error and creates an invalid air object. Importantly, this invalid air expects the API response to follow the JSON dot API error object specification with d DE tales about what went wrong, often including pointers to the specific fields.

Speaker 3

So it expects errors detail marted source pointer data attributes.

Speaker 2

Femail ideally yes. That allows you to easily display validation messages next to the correct form fields. For example, It also maps other codes four one becomes an unauthorized error, four or three of forbidden AER for a four and not founder four on nine a conflict error, and five hundred range usually a server er. These all inherit from a base adapter AIR class.

Speaker 3

That's handy, but what if my API uses say, four hundred bad requests for validation airs instead of four to twenty two.

Speaker 2

You can customize that the adapter has an is invalid status Header's payload method, you can override it to return true. If the status code is four hundred or whatever your API uses telling ember data to treat it as an invalid error.

Speaker 3

Okay, so we can map status codes. What about the error payload itself? What if it's not Jason dot API compliant.

Speaker 2

Two main places to hook in there. For general error response shaping, you can override handle response in adapter that gives you the raw response regardless of status. But if you specifically want to normalize the structure of validation error messages, like transforming your API's custom air format into the json dot api ers array, the extra errors method on the serializer is usually the better place. It's semantically focused on error.

Speaker 3

Payload interpretation adapter for status code mapping and general handling serializer for normalizing the air content.

Speaker 2

Got you got it.

Speaker 3

Let's tackle something a bit more mind vending. Polymorphic relationships, where a relationship can point to different types of records, like a notification could be about a new comment or a friend request. Ah.

Speaker 2

Yes, polymorphism very powerful for certain data models. You enable this in your model by setting polymorphic true on the belongs to or has many relationship definition. The key requirement then falls on the API response When including that relationship data either sideloaded or linked. The API must provide both the ID and the type for each related record.

Speaker 3

So like add five foot type new comment or ABC type friend request.

Speaker 2

Exactly that type tells Ember data which specific model new comment or friend request to load for that relationship link. Of course, those models should ideally inherit from a common base model like notification subject and can.

Speaker 3

You customize how that type information is read or written if the EPI uses a non standard way.

Speaker 2

Absolutely. The serializer offers hooks like key for polymorphic type, serialize polymorphic type, and extract polymorphic relationship to handle custom conventions for identifying and processing those polymorphic types in the payload.

Speaker 3

Incredible flexibility there. It really feels like you can mold MBER data to almost anything, which brings us to testing. With all these potential customizations and adapters and serializers, how do we make sure they actually work correctly and don't break later?

Speaker 2

Testing is absolutely critical. Yes, you wouldn't build a complex machine without testing the parts right. You can unit test adapters and serializers in isolation. For an adapter, you might call EARL four query directly and assert the output URL. For a serializer, you could test key for attribute or normalize with sample payloads.

Speaker 3

Okay, unit tests for specific methods.

Speaker 2

But often the most valuable tests are integration tests that exercise the adapter and serializer together working through the store. This more closely mirrors how your application actually uses them. You'd use the store to find or save a record, and then you can assert things about the outgoing request, like the URL or payload sent by the adapter, serial ether combo, or the data that ends up in the store after normalization.

Speaker 3

And how do you do that without hitting a real API.

Speaker 2

Tools like Embercli Mirage are perfect for this. Mirage lets you easily define mock API endpoints right within your Mber app. So your test run against this predictable mock server. You can make the store fetch data, Mirage intercepts it returns a specific payload you defined, and then you can assert that your serializer normalized it correctly into the store, or assert that saving a record sent the correctly serialized payload to Mirage.

Speaker 3

So Mirage acts as the customized fake back end for testing the whole store adapter serializer stack precisely.

Speaker 2

It gives you high confidence that your data layer customizations are working as intended.

Speaker 3

Right, That makes a lot of sense. Test the whole flow. So let's tie this all together. What's the big takeaway for everyone listening. We've gone through the core part store, adapter, serializer. We've seen how to tweak URLs, map keys, handle nesting, manage errors, even deal with polymorphism.

Speaker 2

I think the main point is that ember data isn't just about fetching data in one specific, prescribed way. It's really about giving you, the developer, the power to create clean abstractions over any kind of API, no matter how complex or non standard it might be. It provides strong conventions as a starting point, which is great for productivity, but it's real strength, it's genius lies in these thoughtful extension points, the adapter and serializer hooks that let you

handle the inevitable real world variations. It frees you up to focus on building the actual features and user experience, rather than getting bogged down in the messy detail of data fetching and translation for every single API call.

Speaker 3

So, whether your API is a perfect JSON dot API implementation or something a bit more creative. From the back end team.

Speaker 4

Mber Data's extensibility means you likely have the tools to make it work cleanly within your MBER application. Hopefully this deep dive has shown you not just how to use these tools, but why they're designed the way they are, empowering you to really master your application's data flow. Think about your own projects. Which of these techniques Overwriting EARL for query, customizing key for attribute, using normalized response might

solve that nagging API integration headache you've been avoiding. The tools are there. That's our time for this deep dive. Until next time, keep exploring, keep customizing, and keep learning.

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