Add how to page on updating hof projects to use axios

wiki/Wiki_How_Tos/3.axios-updates.md

@@ -0,0 +1,161 @@
+---
+title: Replace Request with Axios
+---
+
+This is a basic documentation page to help developer to use an updated version of the HOF framework to implement the replacement of the request.js module with axios. Both modules help developers make HTTP requests for NodeJS applications where a successful request returns a response and a failed request returns an error. The request module is now deprecated and has been replaced with axios in the HOF framework.
+
+
+<br>
+
+```toc
+# This code block gets replaced with the Table Of Contents
+```
+
+
+## Package.json updates
+
+- Specify package to use `hof@~21.0.0`
+- Run `yarn install`
+
+- Make dev use the .env file (command varies on projects)
+```js:title=basic-dev-cmd.js
+"dev": "NODE_ENV=development hof-build watch --env"
+```
+
+## Run the application 
+
+The Hof model uses axios so services do not need to use a standalone axios module. You can require the hof model in your behaviours and models, and access axios using the hof model's request function. 
+
+```
+const Model = require('hof').model;
+```
+
+To access response statuscodes using axios you will need to change the request module's `statusCode` property to `status`.
+
+`response.statusCode`
+becomes 
+`response.status`
+
+To access response data using axios you will need to change the request module's `body` property to `data`.
+`response.body`
+becomes 
+`response.data`
+
+## Breaking changes
+Some behaviours and models will need to be refactored in order to use the updated hof model that uses axios.
+
+### File Uploads
+
+#### Auth model
+
+Use an async/await function to set up the auth model. Note that the `form` property previously used by request has changed to the `data` propertyin the tokenReq object when using axios. To access the access token `response.data.access_token` must be used instead of `response.body.access_token`.
+
+```js:title=models > auth.js
+'use strict';
+
+const Model = require('hof').model;
+const config = require('../../../config');
+
+module.exports = class AuthToken extends Model {
+  async auth() {
+    /* eslint-disable no-console */
+    try {
+      if (!config.keycloak.token) {
+        console.error('keycloak token url is not defined');
+        return {
+          bearer: 'abc123'
+        };
+      }
+      const tokenReq = {
+        url: config.keycloak.token,
+        headers: { 'content-type': 'application/x-www-form-urlencoded' },
+        data: {
+          username: config.keycloak.username,
+          password: config.keycloak.password,
+          grant_type: 'password',
+          client_id: config.keycloak.clientId,
+          client_secret: config.keycloak.secret
+        },
+        method: 'POST'
+      };
+      const response = await this._request(tokenReq);
+      return { bearer: response.data.access_token };
+    } catch (error) {
+      console.error('Error in auth method:', error);
+      throw error;
+    }
+  }
+};
+
+```
+
+#### File upload model
+Axios requires the FormData object to upload files.
+```js:title=models > file-upload.js
+const FormData = require('form-data');
+```
+Set the file data to the form data object and post the request using async/await.
+
+```js:title=models > file-upload.js
+async save() {
+  try {
+    const attributes = {
+      url: config.upload.hostname
+    };
+    const reqConf = url.parse(this.url(attributes));
+
+    const formData = new FormData();
+    formData.append('document', this.get('data'), {
+      filename: this.get('name'),
+      contentType: this.get('mimetype')
+    });
+    reqConf.data = formData;
+    reqConf.method = 'POST';
+    reqConf.headers = {
+         ...formData.getHeaders()
+       };
+
+    const response = await this.request(reqConf);
+
+    return response.data;
+  } catch (err) {
+    console.error('Error in save method:', err);
+    throw err;
+  }
+}
+```
+### HTML to PDF Converter
+#### Additions to PDF model
+Add the rejectUnauthorized and responseType attributes to the requestConfig function
+```js:title=models > pdf.js
+  requestConfig(options) {
+     const settings = super.requestConfig(options);
+     settings.encoding = null;
+     settings.rejectUnauthorized = false;
+     settings.responseType = 'arraybuffer';
+     return settings;
+   }
+```
+
+### Save and Return
+#### Save Form session and Resume Form session
+Create a new instance of the hof model. Then set the url, method and data (if required) parameters to a params object and pass it as an argument to the hof model's request function.
+
+ ```js:title=behaviours > save-form-session.js
+ const Model = require('hof').model;
+ const config = require('../../../config');
+ const _ = require('lodash');
+ ...
+       req.log('info', `Saving Form Session: ${req.sessionModel.get('id')}`);
+
+       const id = req.sessionModel.get('id');
+       const model = new Model();
+       const params = {
+         url: patchUrl(id),
+         data: { session },
+         method: 'PATCH'
+       };
+       return model._request(params, {
+        ...
+       });
+```