✨ Create frontend login mechanism

.idea/runConfigurations/Start_sophon_frontend.xml

@@ -3,7 +3,9 @@
     <package-json value="$PROJECT_DIR$/frontend/package.json" />
     <command value="start" />
     <node-interpreter value="project" />
-    <envs />
+    <envs>
+      <env name="REACT_APP_DEFAULT_INSTANCE_URL" value="http://localhost:30033" />
+    </envs>
     <method v="2" />
   </configuration>
 </component>

frontend/src/App.tsx

@@ -1,6 +1,7 @@
 import * as React from 'react';
 import {Bluelib, Box, Heading, LayoutThreeCol} from "@steffo/bluelib-react";
-import {SophonContextProvider} from "./methods/apiTools";
+import {SophonContextProvider} from "./utils/SophonContext";
+import {LoginBox} from "./components/LoginBox";
 
 function App() {
     return (
@@ -11,9 +12,7 @@ function App() {
                         <Heading level={1}>
                             Sophon
                         </Heading>
-                        <Box>
+                        <LoginBox/>
-                            Welcome to Sophon!
-                        </Box>
                     </LayoutThreeCol.Center>
                 </LayoutThreeCol>
             </Bluelib>

frontend/src/components/LoginBox.tsx

@@ -0,0 +1,78 @@
+import * as React from "react"
+import * as ReactDOM from "react-dom"
+import {Box, Heading, Form, Parenthesis} from "@steffo/bluelib-react";
+import {useSophonContext} from "../utils/SophonContext";
+import {useFormProps} from "../hooks/useValidatedState";
+
+
+interface LoginBoxProps {
+
+}
+
+
+export function LoginBox({...props}: LoginBoxProps): JSX.Element {
+    const {loginData, loginError, login, logout} = useSophonContext()
+
+    const username
+        = useFormProps("",
+            val => {
+                if(val === "") {
+                    return null
+                }
+                return true
+            }
+        )
+    const password
+        = useFormProps("",
+            val => {
+                if(val === "") {
+                    return null
+                }
+                return true
+            }
+        )
+
+
+    if(loginData) {
+        return (
+            <Box>
+                <Heading level={3}>
+                    Login
+                </Heading>
+                <Form>
+                    <Form.Row>
+                        You are logged in as: {loginData.username}
+                    </Form.Row>
+                    <Form.Row>
+                        <Form.Button onClick={logout}>Logout</Form.Button>
+                    </Form.Row>
+                </Form>
+            </Box>
+        )
+    }
+    else {
+        return (
+            <Box>
+                <Heading level={3}>
+                    Login
+                </Heading>
+                <Form>
+                    {loginError ?
+                        <Form.Row>
+                            <Parenthesis bluelibClassNames={"color-red"}>
+                                {loginError.toString()}
+                            </Parenthesis>
+                        </Form.Row>
+                    : null}
+                    <Form.Field label={"Username"} {...username}/>
+                    <Form.Field label={"Password"} type={"password"} {...password}/>
+                    <Form.Row>
+                        <Form.Button onClick={() => login(username.value, password.value)} bluelibClassNames={loginError ? "color-red" : ""}>
+                            Login
+                        </Form.Button>
+                    </Form.Row>
+                </Form>
+            </Box>
+        )
+    }
+}

frontend/src/hooks/useNotNullContext.ts

@@ -0,0 +1,17 @@
+import * as React from "react";
+
+
+export function createNullContext<T>(): React.Context<T | null> {
+    return React.createContext<T | null>(null)
+}
+
+
+export function useNotNullContext<T>(context: React.Context<T | null>): T {
+    const ctx = React.useContext(context)
+
+    if(!ctx) {
+        throw new Error("useNotNullContext called outside its context.")
+    }
+
+    return ctx
+}

frontend/src/hooks/useValidatedState.ts

@@ -0,0 +1,60 @@
+import * as React from "react";
+import {Validity} from "@steffo/bluelib-react/dist/types";
+import {Form} from "@steffo/bluelib-react";
+
+
+/**
+ * A function that checks if a value is acceptable or not for something.
+ *
+ * It can return:
+ * - `true` if the value is acceptable
+ * - `false` if the value is not acceptable
+ * - `null` if no value has been entered by the user
+ */
+export type Validator<T> = (value: T) => Validity
+
+
+/**
+ * The return type of the {@link useValidatedState} hook.
+ */
+export type ValidatedState<T> = [T, React.Dispatch<React.SetStateAction<T>>, Validity]
+
+
+/**
+ * Hook that extends {@link React.useState} by applying a {@link Validator} to the stored value, returning its results to the caller.
+ *
+ * @todo Improve this docstring.
+ * @param def - Default value for the state.
+ * @param validator - The {@link Validator} to apply.
+ */
+export function useValidatedState<T>(def: T, validator: Validator<T>): ValidatedState<T> {
+    const [value, setValue]
+        = React.useState(def)
+
+    const validity
+        = React.useMemo(
+            () => {
+                return validator(value)
+            },
+            [validator, value]
+        )
+
+    return [value, setValue, validity]
+}
+
+
+/**
+ * Hook that changes the return type of {@link useValidatedState} to a {@link Form}-friendly one.
+ *
+ * @param def - Default value for the state.
+ * @param validator - The {@link Validator} to apply.
+ */
+export function useFormProps<T>(def: T, validator: Validator<T>) {
+    const [value, setValue, validity] = useValidatedState<T>(def, validator)
+
+    return {
+        value: value,
+        onSimpleChange: setValue,
+        validity: validity,
+    }
+}

frontend/src/methods/apiTools.tsx

@@ -1,67 +0,0 @@
-import * as React from "react"
-import axios from "axios"
-import {useState} from "react";
-
-
-export type SophonInstanceURL = string
-export type SophonAuthorization = string | null
-
-
-export interface SophonContextContents {
-    instanceUrl: SophonInstanceURL,
-    setInstanceUrl: React.Dispatch<React.SetStateAction<SophonInstanceURL>>,
-
-    authorization: SophonAuthorization,
-    setAuthorization: React.Dispatch<React.SetStateAction<SophonAuthorization>>,
-}
-
-
-export const SophonContext = React.createContext<SophonContextContents | null>(null)
-
-
-export function useSophonContext() {
-    const ctx = React.useContext(SophonContext)
-
-    if(!ctx) {
-        throw new Error("useSophonAxios called outside a SophonContext.")
-    }
-
-    return ctx
-}
-
-
-export function useSophonAxios() {
-    const {instanceUrl, authorization} = useSophonContext()
-
-    return React.useMemo(
-        () => {
-            return axios.create({
-                baseURL: instanceUrl,
-                timeout: 3000,
-                headers: {
-                    "Authorization": authorization,
-                }
-            })
-        },
-        [instanceUrl, authorization]
-    )
-}
-
-
-export interface SophonContextProviderProps {
-    children: React.ReactNode,
-}
-
-
-export function SophonContextProvider({children}: SophonContextProviderProps) {
-    const defaultInstanceUrl = process.env.REACT_APP_DEFAULT_INSTANCE_URL ?? "https://prod.sophon.steffo.eu"
-
-    const [instanceUrl, setInstanceUrl] = useState<SophonInstanceURL>(defaultInstanceUrl)
-    const [authorization, setAuthorization] = useState<SophonAuthorization>(null)
-
-    return (
-        <SophonContext.Provider value={{instanceUrl, setInstanceUrl, authorization, setAuthorization}}>
-            {children}
-        </SophonContext.Provider>
-    )
-}

frontend/src/utils/LoginData.ts

@@ -0,0 +1,35 @@
+import {AxiosInstance, AxiosResponse} from "axios";
+
+
+export interface LoginData {
+    username: string,
+    tokenType: string,
+    token: string,
+}
+
+
+export async function requestLoginData(api: AxiosInstance, username: string, password: string): Promise<LoginData> {
+    console.debug("Requesting auth token...")
+    const response: AxiosResponse<{token: string}> = await api.post("/api/auth/token/", {username, password})
+
+    console.debug("Constructing LoginData...")
+    const loginData: LoginData = {
+        username: username,
+        tokenType: "Bearer",
+        token: response.data.token
+    }
+
+    console.debug("Created LoginData:", loginData)
+    return loginData
+}
+
+
+export function makeAuthorizationHeader(loginData: LoginData | null): {[key: string]: string} {
+    if(loginData === null) {
+        return {}
+    }
+
+    return {
+        "Authorization": `${loginData.tokenType} ${loginData.token}`
+    }
+}

frontend/src/utils/SophonContext.tsx

@@ -0,0 +1,163 @@
+import * as React from "react"
+import Axios, {AxiosInstance} from "axios"
+import {LoginData, makeAuthorizationHeader, requestLoginData} from "./LoginData";
+import {createNullContext, useNotNullContext} from "../hooks/useNotNullContext";
+import {useStorageState} from "../hooks/useStorageState";
+
+
+/**
+ * The type of the `changeSophon` function in {@link SophonContextContents}.
+ */
+export type ChangeSophonFunction = (url: string) => void
+
+/**
+ * The type of the `login` function in {@link SophonContextContents}.
+ */
+export type LoginFunction = (username: string, password: string) => void
+
+/**
+ * The type of the `logout` function in {@link SophonContextContents}.
+ */
+export type LogoutFunction = () => void
+
+
+/**
+ * The contents of the global app context {@link SophonContext}.
+ */
+export interface SophonContextContents {
+    /**
+     * The {@link Axios} instance to use to perform API calls on the Sophon backend.
+     */
+    api: AxiosInstance,
+
+    /**
+     * The {@link LoginData} of the currently logged in user, or `null` if the user is anonymous.
+     */
+    loginData: LoginData | null,
+
+    /**
+     * Whether a login is running or not.
+     */
+    loginRunning: boolean,
+
+    /**
+     * An error that occoured during the login if it happened, `null` otherwise.
+     */
+    loginError: Error | null,
+
+    /**
+     * Login to the Sophon backend with the given `username` and `password`, consequently updating the {@link api} instance.
+     */
+    login: LoginFunction,
+
+    /**
+     * Logout from the Sophon backend, consequently updating the {@link api} instance.
+     */
+    logout: LogoutFunction,
+
+    /**
+     * Change Sophon instance to the one with the given `url`.
+     */
+    changeSophon: ChangeSophonFunction,
+}
+
+/**
+ * The global app context, containing {@link SophonContextContents}.
+ */
+export const SophonContext = createNullContext<SophonContextContents>()
+
+
+/**
+ * Shortcut hook for using the {@link useNotNullContext} hook on {@link SophonContext}.
+ */
+export function useSophonContext(): SophonContextContents {
+    return useNotNullContext(SophonContext)
+}
+
+/**
+ * The props that can be passed to the {@link SophonContextProvider}.
+ */
+export interface SophonContextProviderProps {
+    children?: React.ReactNode,
+}
+
+
+/**
+ * Automatic provider for the global app context {@link SophonContext}.
+ *
+ * No need to do anything with it, except to use it to wrap the whole app.
+ */
+export function SophonContextProvider({children}: SophonContextProviderProps): JSX.Element {
+    const [instanceUrl, setInstanceUrl]
+        = useStorageState<string>(localStorage, "instanceUrl", process.env.REACT_APP_DEFAULT_INSTANCE_URL ?? "https://prod.sophon.steffo.eu")
+
+    const [loginData, setLoginData]
+        = useStorageState<LoginData | null>(localStorage, "loginData", null)
+
+    const [loginError, setLoginError]
+        = React.useState<Error | null>(null)
+
+    const [loginRunning, setLoginRunning]
+        = React.useState<boolean>(false)
+
+    const api: AxiosInstance
+        = React.useMemo(
+            () => {
+                console.debug("Creating new AxiosInstance...")
+                return Axios.create({
+                    baseURL: instanceUrl,
+                    timeout: 3000,
+                    headers: {
+                        ...makeAuthorizationHeader(loginData)
+                    }
+                })
+            },
+            [instanceUrl, loginData]
+        )
+
+    const login: LoginFunction
+        = React.useCallback(
+            (username, password) => {
+                console.info("Trying to login as", username, "...")
+                setLoginRunning(true)
+                setLoginError(null)
+                requestLoginData(api, username, password)
+                    .then(loginData => setLoginData(loginData))
+                    .catch(error => setLoginError(error))
+                    .finally(() => setLoginRunning(false))
+            },
+            [api, setLoginData, setLoginRunning, setLoginError]
+        )
+
+    const logout: LogoutFunction = React.useCallback(
+        () => {
+            if(loginRunning) {
+                throw Error("Refusing to logout while a login is running.")
+            }
+            console.info("Logging out...")
+            setLoginData(null)
+        },
+        [setLoginData]
+    )
+
+    const changeSophon: ChangeSophonFunction = React.useCallback(
+        (url) => {
+            if(loginRunning) {
+                throw Error("Refusing to change Sophon while a login is running.")
+            }
+            if(loginData) {
+                console.debug("Logging out user before changing Sophon...")
+                logout()
+            }
+            console.info("Changing Sophon to ", url, "...")
+            setInstanceUrl(url)
+        },
+        [logout, setInstanceUrl, loginRunning, loginData]
+    )
+
+    return (
+        <SophonContext.Provider value={{api, loginData, loginRunning, loginError, login, logout, changeSophon}}>
+            {children}
+        </SophonContext.Provider>
+    )
+}