I recently worked on updating an app I made a couple of years ago, that was using Yelp’s API. I was running into some issues deploying the older version of the app to Heroku, so I decided to update the API it was using to the latest version for Yelp, v3.
As I’m writing this, I found that the Yelp API documentation was a little confusing. The older API required a consumer key, consumer secret, token, and token secret. The Yelp Fusion API only requires an Authorization parameter.
Authentication for the Yelp API is outlined here, although I had to do a bit of fiddling around until I was able to successfully make an API GET request. Here’s what Postman looked like once I was able to make a successful call (click the image to see a larger view):
Something I wasn’t aware of from the APIs I’ve worked with, is that the Headers required a
Content-Type with the value
application/json and an
Authorization with a value that started with the word Bearer, a space, and then the API key I had received from Yelp. So the value looked something like
If you’re curious about how I wrote the code for my application, you can take a look at my github repo for the app, What am I Even Doing?
An API is a set of routines or functions. It’s an interface used for performing tasks, retrieving data, and manipulating data. APIs use HTTP methods, which are used on a resource to GET, POST (submit form data), PUT (for updating files), PATCH (a partial update), and DELETE.
Adding an API
- Bolt-on strategy – when you already have an application and are adding an API to it
- Greenfield strategy – no underlining application. There’s complete freedom and flexibility to do what you want. Generally the “API first” or “mobile first” mentality.
- Facade strategy – wraps existing logic with replace as you go. This is ideal for legacy systems so the application is always functional.
Designing the Relationship
- Independent – the resources may exist regardless of the other existing but they may reference each other
- Dependent – one resource cannot exist without the parent
- Associative – they are independent of each other but the relationship contains additional properties to describe it
Planning the Relationships
- Ask yourself the following questions:
- Can both resources exist without the other?
- Does one resource only exist when the other exists?
- Does the relationship between resources require more information than just the links between them?
- It should be relatively easy to map out the flow, action, etc for each resource. If not, you need to revise your design.
- Consider using notecards to write down each resource action
- REST stands for Representational State Transfer
- It’s an architecture for designing network-based applications
- It is not a protocol, framework, or standard
Benefits of Stateless Servers
- Visibility – monitoring systems and developers do not need to look beyond the request to trace a bug
- Reliability – easy to recover from system failures
Drawbacks of Stateless Servers
- Network Bandwidth – client sends state for every request
- Complexity – all clients must handle their states
Benefits of Caching
- Performance – for stateless and caching, many requests do not need to go all the way to the server
- Scalability – server gets fewer requests so it can handle more clients
Drawbacks of Caching
- Data reliability – clients might use stale data
Facets of a Uniform Interface
- Self descriptive messages
- Server includes metadata, such as Content-Type, to help clients process the responses
- Hypermedia as the engine of application state (HATEOAS)
- Client only assumes a fixed entry-point to the API, the server tells clients all other available actions through hyperlinksBenefits of a Layered System
- Encapsulation (simplify an interface to a legacy server)
- Scalability (layers enable load balancing)
- Security (add access control rules to data crossing a boundary, just like a firewall)
Drawbacks of a Layered System
- Latency – adding layers increases latency
GraphQL is a query language designed to make data fetching easier. It allows you to get data from the server to the client. It is language agnostic and became open source in 2015.
- Input types include: integer, float, string, boolean, null, enum, list, object
- It has a built-in documentation for the schema
- Can create operation names to help identify different queries
- Creates changes through mutations
- API determines what mutations are allowed
- Avoids multiple REST calls
- Is backward compatible and version-free
- Can wrap around existing APIs
- Queries can have comments
Recently I did some document diving to find out more about different styles of software design. When it comes to building software, I’m someone who is more familiar with getting things to work, and I haven’t focused too much attention on discussing my approaches. So in an effort to become more eloquent about the way I describe my work, I thought I’d share an overview on software design styles and the cycle of software design:
Service-oriented architecture (SOA): a style of software design where services are provided with application components through a communication protocol over a network. The elements of SOA include:
- Application frontend, service, service repository, service bus
- Contract, implementation, interface
- Business logic, data
A web service is an example of an SOA with a well-defined set of implementation choices.
Representational state transfer (RESTful): RESTful web services allow systems to access and manipulate web resources by using a predefined set of operations. RESTful includes the HTTP methods get, put, post, and delete. More information on what these mean include the following:
- Get: retrieves a representation of the collection
- Put: replaces the addressed item of a collection, or if it doesn’t exist, it creates it
- Post: create a new entry in the collection
- Delete: delete the item in a collection
Model-view-controller (MVC): a pattern for implementing user interfaces. It’s broken down into three components:
- Model: directly manages the data and logic of the application
- View: the output of the information, how the information is presented to the user
- Controller: uses input from the user to make changes to the model or view
Software development life cycle (SDLC): a structured sequence of stages in developing a software product. These steps include: communication, requirement gathering, feasibility study, system analysis, software design, coding, testing, integration, implementation, operations & maintenance, and disposition.