7 files changed, 355 insertions, 0 deletions
diff --git a/app_expo/services/api/api-config.ts b/app_expo/services/api/api-config.ts
new file mode 100644
index 0000000..b939c0e
--- /dev/null
+++ b/app_expo/services/api/api-config.ts
@@ -0,0 +1,27 @@
+// Use this import if you want to use "env.js" file
+// const { API_URL } = require("../../config/env")
+// Or just specify it directly like this:
+const API_URL = 'http://example.com'
+
+/**
+ * The options used to configure the API.
+ */
+export interface ApiConfig {
+  /**
+   * The URL of the api.
+   */
+  url: string
+
+  /**
+   * Milliseconds before we timeout the request.
+   */
+  timeout: number
+}
+
+/**
+ * The default configuration for the app.
+ */
+export const DEFAULT_API_CONFIG: ApiConfig = {
+  url: API_URL || 'https://jsonplaceholder.typicode.com',
+  timeout: 10000,
+}
diff --git a/app_expo/services/api/api-problem.test.ts b/app_expo/services/api/api-problem.test.ts
new file mode 100644
index 0000000..f8b4041
--- /dev/null
+++ b/app_expo/services/api/api-problem.test.ts
@@ -0,0 +1,100 @@
+import { getGeneralApiProblem } from './api-problem'
+import { ApiErrorResponse } from 'apisauce'
+
+test('handles connection errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'CONNECTION_ERROR',
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'cannot-connect',
+    temporary: true,
+  })
+})
+
+test('handles network errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'NETWORK_ERROR',
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'cannot-connect',
+    temporary: true,
+  })
+})
+
+test('handles timeouts', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'TIMEOUT_ERROR',
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'timeout',
+    temporary: true,
+  })
+})
+
+test('handles server errors', () => {
+  expect(getGeneralApiProblem({ problem: 'SERVER_ERROR' } as ApiErrorResponse<null>)).toEqual({
+    kind: 'server',
+  })
+})
+
+test('handles unknown errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'UNKNOWN_ERROR',
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'unknown',
+    temporary: true,
+  })
+})
+
+test('handles unauthorized errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'CLIENT_ERROR',
+      status: 401,
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'unauthorized',
+  })
+})
+
+test('handles forbidden errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'CLIENT_ERROR',
+      status: 403,
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'forbidden',
+  })
+})
+
+test('handles not-found errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'CLIENT_ERROR',
+      status: 404,
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'not-found',
+  })
+})
+
+test('handles other client errors', () => {
+  expect(
+    getGeneralApiProblem({
+      problem: 'CLIENT_ERROR',
+      status: 418,
+    } as ApiErrorResponse<null>),
+  ).toEqual({
+    kind: 'rejected',
+  })
+})
+
+test('handles cancellation errors', () => {
+  expect(getGeneralApiProblem({ problem: 'CANCEL_ERROR' } as ApiErrorResponse<null>)).toBeNull()
+})
diff --git a/app_expo/services/api/api-problem.ts b/app_expo/services/api/api-problem.ts
new file mode 100644
index 0000000..15ca850
--- /dev/null
+++ b/app_expo/services/api/api-problem.ts
@@ -0,0 +1,74 @@
+import { ApiResponse } from 'apisauce'
+
+export type GeneralApiProblem =
+  /**
+   * Times up.
+   */
+  | { kind: 'timeout'; temporary: true }
+  /**
+   * Cannot connect to the server for some reason.
+   */
+  | { kind: 'cannot-connect'; temporary: true }
+  /**
+   * The server experienced a problem. Any 5xx error.
+   */
+  | { kind: 'server' }
+  /**
+   * We're not allowed because we haven't identified ourself. This is 401.
+   */
+  | { kind: 'unauthorized' }
+  /**
+   * We don't have access to perform that request. This is 403.
+   */
+  | { kind: 'forbidden' }
+  /**
+   * Unable to find that resource.  This is a 404.
+   */
+  | { kind: 'not-found' }
+  /**
+   * All other 4xx series errors.
+   */
+  | { kind: 'rejected' }
+  /**
+   * Something truly unexpected happened. Most likely can try again. This is a catch all.
+   */
+  | { kind: 'unknown'; temporary: true }
+  /**
+   * The data we received is not in the expected format.
+   */
+  | { kind: 'bad-data' }
+
+/**
+ * Attempts to get a common cause of problems from an api response.
+ *
+ * @param response The api response.
+ */
+export function getGeneralApiProblem(response: ApiResponse<any>): GeneralApiProblem | void {
+  switch (response.problem) {
+    case 'CONNECTION_ERROR':
+      return { kind: 'cannot-connect', temporary: true }
+    case 'NETWORK_ERROR':
+      return { kind: 'cannot-connect', temporary: true }
+    case 'TIMEOUT_ERROR':
+      return { kind: 'timeout', temporary: true }
+    case 'SERVER_ERROR':
+      return { kind: 'server' }
+    case 'UNKNOWN_ERROR':
+      return { kind: 'unknown', temporary: true }
+    case 'CLIENT_ERROR':
+      switch (response.status) {
+        case 401:
+          return { kind: 'unauthorized' }
+        case 403:
+          return { kind: 'forbidden' }
+        case 404:
+          return { kind: 'not-found' }
+        default:
+          return { kind: 'rejected' }
+      }
+    case 'CANCEL_ERROR':
+      return null
+  }
+
+  return null
+}
diff --git a/app_expo/services/api/api.ts b/app_expo/services/api/api.ts
new file mode 100644
index 0000000..4093d34
--- /dev/null
+++ b/app_expo/services/api/api.ts
@@ -0,0 +1,102 @@
+import { ApisauceInstance, create, ApiResponse } from 'apisauce'
+import { getGeneralApiProblem } from './api-problem'
+import { ApiConfig, DEFAULT_API_CONFIG } from './api-config'
+import * as Types from './api.types'
+
+/**
+ * Manages all requests to the API.
+ */
+export class Api {
+  /**
+   * The underlying apisauce instance which performs the requests.
+   */
+  apisauce: ApisauceInstance
+
+  /**
+   * Configurable options.
+   */
+  config: ApiConfig
+
+  /**
+   * Creates the api.
+   *
+   * @param config The configuration to use.
+   */
+  constructor(config: ApiConfig = DEFAULT_API_CONFIG) {
+    this.config = config
+  }
+
+  /**
+   * Sets up the API.  This will be called during the bootup
+   * sequence and will happen before the first React component
+   * is mounted.
+   *
+   * Be as quick as possible in here.
+   */
+  setup() {
+    // construct the apisauce instance
+    this.apisauce = create({
+      baseURL: this.config.url,
+      timeout: this.config.timeout,
+      headers: {
+        Accept: 'application/json',
+      },
+    })
+  }
+
+  /**
+   * Gets a list of users.
+   */
+  async getUsers(): Promise<Types.GetUsersResult> {
+    // make the api call
+    const response: ApiResponse<any> = await this.apisauce.get(`/users`)
+
+    // the typical ways to die when calling an api
+    if (!response.ok) {
+      const problem = getGeneralApiProblem(response)
+      if (problem) return problem
+    }
+
+    const convertUser = (raw) => {
+      return {
+        id: raw.id,
+        name: raw.name,
+      }
+    }
+
+    // transform the data into the format we are expecting
+    try {
+      const rawUsers = response.data
+      const resultUsers: Types.User[] = rawUsers.map(convertUser)
+      return { kind: 'ok', users: resultUsers }
+    } catch {
+      return { kind: 'bad-data' }
+    }
+  }
+
+  /**
+   * Gets a single user by ID
+   */
+
+  async getUser(id: string): Promise<Types.GetUserResult> {
+    // make the api call
+    const response: ApiResponse<any> = await this.apisauce.get(`/users/${id}`)
+
+    // the typical ways to die when calling an api
+    if (!response.ok) {
+      const problem = getGeneralApiProblem(response)
+      if (problem) return problem
+    }
+
+    // transform the data into the format we are expecting
+    try {
+      const resultUser: Types.User = {
+        id: response.data.id,
+        name: response.data.name,
+      }
+      return { kind: 'ok', user: resultUser }
+    } catch {
+      return { kind: 'bad-data' }
+    }
+  }
+}
diff --git a/app_expo/services/api/api.types.ts b/app_expo/services/api/api.types.ts
new file mode 100644
index 0000000..21d3c87
--- /dev/null
+++ b/app_expo/services/api/api.types.ts
@@ -0,0 +1,13 @@
+import { GeneralApiProblem } from './api-problem'
+import { Character } from '../../models/character/character'
+
+export interface User {
+  id: number
+  name: string
+}
+
+export type GetUsersResult = { kind: 'ok'; users: User[] } | GeneralApiProblem
+export type GetUserResult = { kind: 'ok'; user: User } | GeneralApiProblem
+
+export type GetCharactersResult = { kind: 'ok'; characters: Character[] } | GeneralApiProblem
+export type GetCharacterResult = { kind: 'ok'; character: Character } | GeneralApiProblem
diff --git a/app_expo/services/api/character-api.ts b/app_expo/services/api/character-api.ts
new file mode 100644
index 0000000..e28ec48
--- /dev/null
+++ b/app_expo/services/api/character-api.ts
@@ -0,0 +1,37 @@
+import { ApiResponse } from 'apisauce'
+import { Api } from './api'
+import { GetCharactersResult } from './api.types'
+import { getGeneralApiProblem } from './api-problem'
+
+const API_PAGE_SIZE = 50
+
+export class CharacterApi {
+  private api: Api
+
+  constructor(api: Api) {
+    this.api = api
+  }
+
+  async getCharacters(): Promise<GetCharactersResult> {
+    try {
+      // make the api call
+      const response: ApiResponse<any> = await this.api.apisauce.get(
+        'https://raw.githubusercontent.com/infinitered/ignite/master/data/rick-and-morty.json',
+        { amount: API_PAGE_SIZE },
+      )
+
+      // the typical ways to die when calling an api
+      if (!response.ok) {
+        const problem = getGeneralApiProblem(response)
+        if (problem) return problem
+      }
+
+      const characters = response.data.results
+
+      return { kind: 'ok', characters }
+    } catch (e) {
+      __DEV__ && console.tron.log(e.message)
+      return { kind: 'bad-data' }
+    }
+  }
+}
diff --git a/app_expo/services/api/index.ts b/app_expo/services/api/index.ts
new file mode 100644
index 0000000..f133e64
--- /dev/null
+++ b/app_expo/services/api/index.ts
@@ -0,0 +1,2 @@
+export * from './api'
+export * from './api.types'