|
| 1 | +--- |
| 2 | +title: "Exchange Information Between Active Views Using Web API" |
| 3 | +linktitle: "Communication Between Views" |
| 4 | +url: /apidocs-mxsdk/apidocs/web-extensibility-api-11/message-passing-api/ |
| 5 | +--- |
| 6 | + |
| 7 | +## Introduction |
| 8 | + |
| 9 | +This how-to describes how to pass information between different active views (such as tabs, dialogs, and panes) within the same extension. |
| 10 | + |
| 11 | +## Prerequisites |
| 12 | + |
| 13 | +Before starting this how-to, make sure you have completed the following prerequisites: |
| 14 | + |
| 15 | +* This how-to uses the results of [Get Started with the Web Extensibility API](/apidocs-mxsdk/apidocs/web-extensibility-api-11/getting-started/). Complete that how-to before starting this one. |
| 16 | +* Make sure you are familiar with: |
| 17 | + * Creating [menus](/apidocs-mxsdk/apidocs/web-extensibility-api-11/menu-api/) |
| 18 | + * Creating different kinds of views, such as [tabs](/apidocs-mxsdk/apidocs/web-extensibility-api-11/tab-api/) and [panes](/apidocs-mxsdk/apidocs/web-extensibility-api-11/dockable-pane-api/) |
| 19 | + |
| 20 | +## Communication Patterns |
| 21 | + |
| 22 | +Use the Message Passing API to pass information between different active contexts within an extension (such as its main entry point and active views). Access this API via `studioPro.ui.messagePassing`, where `studioPro` refers to the Studio Pro object returned by the `getStudioProApi` call. |
| 23 | + |
| 24 | +This API supports two communication patterns: request-reply and message broadcasting. |
| 25 | + |
| 26 | +### Request-Reply |
| 27 | + |
| 28 | +In the request-reply pattern, one endpoint sends a message to another endpoint and waits for a reply. The Message Passing API supports this pattern by allowing the sender to include a callback function, which is triggered when a reply is received. |
| 29 | + |
| 30 | +To implement this behavior, insert the following code in `main/index.ts`: |
| 31 | + |
| 32 | +```typescript {hl_lines=["16-25"]} |
| 33 | +import { IComponent, getStudioProApi } from "@mendix/extensions-api"; |
| 34 | + |
| 35 | +export const component: IComponent = { |
| 36 | + async loaded(componentContext) { |
| 37 | + const studioPro = getStudioProApi(componentContext); |
| 38 | + let counter = 0; |
| 39 | + // Add a menu item to the Extensions menu |
| 40 | + await studioPro.ui.extensionsMenu.add({ |
| 41 | + menuId: "message-passing.MainMenu", |
| 42 | + caption: "Message passing", |
| 43 | + subMenus: [ |
| 44 | + { menuId: "message-passing.ShowTab", caption: "Show tab" }, |
| 45 | + ], |
| 46 | + }); |
| 47 | + |
| 48 | + await studioPro.ui.messagePassing.addMessageHandler<{type:string}>(async messageInfo => { |
| 49 | + const messageData = messageInfo.message; |
| 50 | + if (messageData.type === "incrementCounter") { |
| 51 | + counter++; |
| 52 | + await studioPro.ui.messagePassing.sendResponse(messageInfo.messageId, { |
| 53 | + type: "counterValue", |
| 54 | + counter |
| 55 | + }); |
| 56 | + } |
| 57 | + }); |
| 58 | + |
| 59 | + // Open a tab when the menu item is clicked |
| 60 | + studioPro.ui.extensionsMenu.addEventListener( |
| 61 | + "menuItemActivated", |
| 62 | + async (args) => { |
| 63 | + if (args.menuId === "message-passing.ShowTab") { |
| 64 | + await studioPro.ui.tabs.open( |
| 65 | + { |
| 66 | + title: "MyExtension Tab" |
| 67 | + }, |
| 68 | + { |
| 69 | + componentName: "extension/message-passing", |
| 70 | + uiEntrypoint: "tab", |
| 71 | + } |
| 72 | + ); |
| 73 | + } |
| 74 | + } |
| 75 | + ); |
| 76 | + } |
| 77 | +} |
| 78 | +``` |
| 79 | + |
| 80 | +Insert the following code into `src/ui/index.tsx`: |
| 81 | + |
| 82 | +```typescript {hl_lines=["14-19"]} |
| 83 | +import React, { StrictMode, useCallback, useState } from "react"; |
| 84 | +import { createRoot } from "react-dom/client"; |
| 85 | +import { ComponentContext, getStudioProApi, IComponent } from "@mendix/extensions-api"; |
| 86 | + |
| 87 | + |
| 88 | +type MessagePassingAppProps = { |
| 89 | + componentContext: ComponentContext |
| 90 | +} |
| 91 | + |
| 92 | +function CounterState({ componentContext }: MessagePassingAppProps) { |
| 93 | + const studioPro = getStudioProApi(componentContext); |
| 94 | + const [counter, setCounter] = useState<number | null>(null); |
| 95 | + const incrementCounter = useCallback(async () => { |
| 96 | + studioPro.ui.messagePassing.sendMessage( |
| 97 | + { type: "incrementCounter"}, |
| 98 | + async (response: {type: 'counterValue', counter: number}) => { |
| 99 | + setCounter(response.counter); |
| 100 | + } |
| 101 | + ); |
| 102 | + }, [componentContext]); |
| 103 | + |
| 104 | + return ( |
| 105 | + <div> |
| 106 | + <button onClick={incrementCounter}> Increment counter </button> |
| 107 | + <p> Counter value: {counter ?? "unknown"} </p> |
| 108 | + </div> |
| 109 | + ); |
| 110 | +} |
| 111 | + |
| 112 | +export const component: IComponent = { |
| 113 | + async loaded(componentContext) { |
| 114 | + createRoot(document.getElementById("root")!).render( |
| 115 | + <StrictMode> |
| 116 | + <CounterState componentContext={componentContext} /> |
| 117 | + </StrictMode> |
| 118 | + ); |
| 119 | + } |
| 120 | +} |
| 121 | +``` |
| 122 | + |
| 123 | +In this example, the extension increases the `counter` value in the main context every time the user clicks a button in the active tab. To achieve this, the tab sends a message to the main context, expecting a reply with the current `counter` value. |
| 124 | + |
| 125 | +The highlighted lines demonstrate how to respond to a message. In the main context (`src/main/index.ts`), a listener is registered, which handles incoming messages from other contexts. Each message has an ID, which can be used to identify and respond to that specific message. |
| 126 | + |
| 127 | +When the main context sends a response, it is received by the `onResponse` callback registered in |
| 128 | +the highlighted lines of `src/ui/index.tsx`. Note that this callback will be invoked only once, |
| 129 | +as each message can have a single response. |
| 130 | + |
| 131 | +### Broadcast |
| 132 | + |
| 133 | +In the broadcast pattern, one context sends a messages to all other contexts that are listening for it. To implement this pattern, do the following: |
| 134 | + |
| 135 | +1. Copy the following code into `src/main/index.ts`: |
| 136 | + |
| 137 | + ```typescript |
| 138 | + import { IComponent, getStudioProApi } from "@mendix/extensions-api"; |
| 139 | + |
| 140 | + export const component: IComponent = { |
| 141 | + async loaded(componentContext) { |
| 142 | + const studioPro = getStudioProApi(componentContext); |
| 143 | + let counter = 0; |
| 144 | + // Add a menu item to the Extensions menu |
| 145 | + await studioPro.ui.extensionsMenu.add({ |
| 146 | + menuId: "message-passing.MainMenu", |
| 147 | + caption: "Message Passing", |
| 148 | + subMenus: [ |
| 149 | + { menuId: "message-passing.ShowTab", caption: "Show tab" }, |
| 150 | + { menuId: "message-passing.ShowPane", caption: "Show pane" }, |
| 151 | + ], |
| 152 | + }); |
| 153 | + |
| 154 | + const paneHandle = await studioPro.ui.panes.register({ |
| 155 | + title: 'Message Passing Pane', |
| 156 | + initialPosition: 'right', |
| 157 | + }, { |
| 158 | + componentName: "extension/message-passing", |
| 159 | + uiEntrypoint: "pane" |
| 160 | + }) |
| 161 | + |
| 162 | + // Open a tab when the menu item is clicked |
| 163 | + studioPro.ui.extensionsMenu.addEventListener( |
| 164 | + "menuItemActivated", |
| 165 | + async (args) => { |
| 166 | + if (args.menuId === "message-passing.ShowTab") { |
| 167 | + await studioPro.ui.tabs.open( |
| 168 | + { |
| 169 | + title: "MyExtension Tab" |
| 170 | + }, |
| 171 | + { |
| 172 | + componentName: "extension/message-passing", |
| 173 | + uiEntrypoint: "tab", |
| 174 | + } |
| 175 | + ); |
| 176 | + } else if (args.menuId === "message-passing.ShowPane") { |
| 177 | + await studioPro.ui.panes.open(paneHandle); |
| 178 | + } |
| 179 | + } |
| 180 | + ); |
| 181 | + } |
| 182 | + } |
| 183 | + ``` |
| 184 | + |
| 185 | +2. Rename `src/ui/index.tsx` to `src/ui/tab.tsx` and paste the following code into it: |
| 186 | + |
| 187 | + ```typescript {hl_lines=["13-15"]} |
| 188 | + import React, { StrictMode, useCallback, useEffect, useState } from "react"; |
| 189 | + import { createRoot } from "react-dom/client"; |
| 190 | + import { ComponentContext, getStudioProApi, IComponent } from "@mendix/extensions-api"; |
| 191 | +
|
| 192 | +
|
| 193 | + type MessagePassingAppProps = { |
| 194 | + componentContext: ComponentContext |
| 195 | + } |
| 196 | +
|
| 197 | + function NameBroadcaster({ componentContext }: MessagePassingAppProps) { |
| 198 | + const studioPro = getStudioProApi(componentContext); |
| 199 | + const [name, setName] = useState<string>(""); |
| 200 | + useEffect(() => { |
| 201 | + studioPro.ui.messagePassing.sendMessage({ type: "nameChanged", name }); |
| 202 | + }, [name]); |
| 203 | +
|
| 204 | + return ( |
| 205 | + <div> |
| 206 | + Name: <input value={name} onChange={e => setName(e.target.value)} /> |
| 207 | + </div> |
| 208 | + ); |
| 209 | + } |
| 210 | +
|
| 211 | + export const component: IComponent = { |
| 212 | + async loaded(componentContext) { |
| 213 | + createRoot(document.getElementById("root")!).render( |
| 214 | + <StrictMode> |
| 215 | + <NameBroadcaster componentContext={componentContext} /> |
| 216 | + </StrictMode> |
| 217 | + ); |
| 218 | + } |
| 219 | + } |
| 220 | + ``` |
| 221 | + |
| 222 | +3. Create a new file `src/ui/pane.tsx` and paste the following code into it: |
| 223 | + |
| 224 | + ```typescript {hl_lines=["14-19"]} |
| 225 | + import React, { StrictMode, useCallback, useEffect, useState } from "react"; |
| 226 | + import { createRoot } from "react-dom/client"; |
| 227 | + import { ComponentContext, getStudioProApi, IComponent } from "@mendix/extensions-api"; |
| 228 | +
|
| 229 | +
|
| 230 | + type MessagePassingAppProps = { |
| 231 | + componentContext: ComponentContext |
| 232 | + } |
| 233 | +
|
| 234 | + function Greeter({ componentContext }: MessagePassingAppProps) { |
| 235 | + const studioPro = getStudioProApi(componentContext); |
| 236 | + const [name, setName] = useState<string>("unknown"); |
| 237 | + useEffect(() => { |
| 238 | + studioPro.ui.messagePassing.addMessageHandler<{ type: string; name: string }>(async messageInfo => { |
| 239 | + const messageData = messageInfo.message; |
| 240 | + if (messageData.type === "nameChanged") { |
| 241 | + setName(messageData.name); |
| 242 | + } |
| 243 | + }); |
| 244 | + }, [componentContext]); |
| 245 | +
|
| 246 | + return ( |
| 247 | + <div> |
| 248 | + Hello {name}! |
| 249 | + </div> |
| 250 | + ); |
| 251 | + } |
| 252 | +
|
| 253 | + export const component: IComponent = { |
| 254 | + async loaded(componentContext) { |
| 255 | + createRoot(document.getElementById("root")!).render( |
| 256 | + <StrictMode> |
| 257 | + <Greeter componentContext={componentContext} /> |
| 258 | + </StrictMode> |
| 259 | + ); |
| 260 | + } |
| 261 | + } |
| 262 | + ``` |
| 263 | + |
| 264 | +4. Update `build-extension.mjs` by replacing the `entryPoints` array with: |
| 265 | + |
| 266 | + ```javascript |
| 267 | + const entryPoints = [ |
| 268 | + { |
| 269 | + in: 'src/main/index.ts', |
| 270 | + out: 'main' |
| 271 | + } |
| 272 | + ] |
| 273 | +
|
| 274 | + entryPoints.push({ |
| 275 | + in: 'src/ui/tab.tsx', |
| 276 | + out: 'tab' |
| 277 | + }) |
| 278 | +
|
| 279 | + entryPoints.push({ |
| 280 | + in: 'src/ui/pane.tsx', |
| 281 | + out: 'pane' |
| 282 | + }) |
| 283 | + ``` |
| 284 | + |
| 285 | +5. Replace the contents of `manifest.json` with: |
| 286 | + |
| 287 | + ``` |
| 288 | + { |
| 289 | + "mendixComponent": { |
| 290 | + "entryPoints": { |
| 291 | + "main": "main.js", |
| 292 | + "ui": { |
| 293 | + "tab": "tab.js", |
| 294 | + "pane": "pane.js" |
| 295 | + } |
| 296 | + } |
| 297 | + } |
| 298 | + } |
| 299 | + ``` |
| 300 | + |
| 301 | +This setup ensures that both the tab and the pane are registered in `src/main/index.ts`. |
| 302 | +The tab sends a message whenever the `name` value is updated. The pane listens for these messages emitted from the tab, and updates its |
| 303 | +view accordingly each time a new message is received. |
| 304 | + |
| 305 | +## Extensibility Feedback |
| 306 | + |
| 307 | +If you would like to provide us with additional feedback, you can complete a small [survey](https://survey.alchemer.eu/s3/90801191/Extensibility-Feedback). |
| 308 | + |
| 309 | +Any feedback is appreciated. |
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