https://help.sap.com/viewer/4505d0bdaf4948449b7f7379d24d0f0d/2.0.03/en-US/31d5595ee67c484290621fdc6d6a197f.html
本系列文章我们将介绍如何为 SAP S4HANA Cloud 系统开发扩展程序 （Extension App）。本文（项目源代码可下载自 GitLab sourcecode）将介绍如何在同一个 Node.js Application 里将传统 Express 程序与 SAP HANA XSJS 程序结合使用。
回到我们的第一篇 SAP Cloud Foundry Node.js - Getting Started with SAP Cloud SDK TypeScript version 介绍了怎么 Setup 起来一个 TypeScript 版的 Node.js Application，本篇接着改进它，使其支持 SAP HANA XSJS 程序。
Step 1. Init XSJS in Express Application
npm install @sap/xsjs --save
npm install @sap/hdbext --save
cf set-env my-cloud-sdk-demo XS_APP_LOG_LEVEL debug
Check the Standard Node.js Packages for XS Advanced
@sap/logging
@sap/hdbext
@sap/audit-logging
Error: XS Application User
添加 HANA Ext 的 middleware 函数时会出现如下错误：
{“code”:455,”message”:”the predefined session variable cannot be set via SET command: XS_APPLICATIONUSER”,”sqlState”:”HY000”,”status”:500}
经过如下重现过程后发现 getRequestOptions from req 会取出 sessionVariable:XS_APPLICATIONUSER 并传给 createConnection 而它并不需要 Application User 去连 HANA DB 而是通过 hanaService 提供的用户信息
const services = xsenv.getServices({ uaa:'my-xsuaa' });
passport.use(new JWTStrategy(services.uaa));
this.app.use(passport.initialize());
this.app.use(passport.authenticate('JWT', { session: false }));
function middleware(hanaService) {
/**
* {
* "sessionVariable:APPLICATION":"my-cloud-sdk-demo/dev",
* "sessionVariable:APPLICATIONVERSION":"my-cloud-sdk-demo@1.0.0"
* }
*/
console.error(JSON.stringify(connOptions.getGlobalOptions()));
var globalOptions = _.extend({}, connOptions.getGlobalOptions(), hanaService);
/**
* {
* "sessionVariable:APPLICATION":"my-cloud-sdk-demo/dev",
* "sessionVariable:APPLICATIONVERSION":"my-cloud-sdk-demo@1.0.0",
* "host":"10.253.93.93",
* "port":"30041",
* "driver":"com.sap.db.jdbc.Driver",
* "url":"jdbc:sap://10.253.93.93:30041/?currentschema=3F5AE825FC7A4C5C97A3A01FD53AF6",
* "schema":"3F5AE825FC7A4C5C9FA7A01FD53AF6",
* "hdi_user":"SBSS_852183372522635697759010499289880709458540037505389095323186432",
* "hdi_password":"Rl8oKkR5z2n1ay4BBgnfglvPoYrcdHjR-_v0_eSuRRBOrvIzQfTN3gQL7vrJNA6edxHEuQmhJZXKpXX6u8.iXHk1HRoWuVxnq9Uu354snqIrE-u_.-IKjDiWWGJ0ev",
* "user":"SBSS_485141804469823880835309905005045141010551400530012062819396603",
* "password":"Uo6bS07rc1JNS9ALWATWXCW30_YZ1wfhUcsJvHSbujvdb8tgwRNRMYsKAnpd_VZdbmF3-MiSp3h8SnFmKawA-rMJHISq4zALYEWFs.Vb5S_23NwKazRT959TO0Hqby"
* }
*/
console.error(JSON.stringify(globalOptions));
return function db(req, res, next) {
var requestOptions = connOptions.getRequestOptions(req);
/**
* {
* "sessionVariable:XS_APPLICATIONUSER":"eyJhbGciOiJSUzI1NiIsImprdSI6Imh0dHBzOi8vcDIwMDEyODUzNzV0cmlhbC5hdXRoZW50aWNhdGlvbi5ldTEwLmhhbmEub25kZW1hbmQuY29tL3Rva2VuX2tleXMiLCJraWQiOiJrZXktaWQtMSIsInR5cCI6IkpXVCJ9.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.E-ljDMvwjXjNc71eJKsHByv7d7SGuU_OC4rvGeIq3FsOzi8I8yUHbln5r1CIYlhDnroJg6rF97KY_fvhgFY8cV3zPJP4_Zjq7dwWJpRZv6n_LdR8rE8mjtOH4rFy2yxxIie8vKPbAzNwf-fqnjwbP5-gBdB_0i3K6PVjwqatrq0L7k884CaBZXPiFV8Xrffgwtdph3UMGuuw1n3hO3lSNLd8wl2t2nrqq8wH7inYJkxlZ2tsGtMU9Plp0-n8isX-75SffQQlsdHFcFLuRjFJT64YgywU13wBpuXx7ihK2JA7TmDah9YbWTNe4vkaJsZ8z2Jwaznr_8GiBKry8VDriLgjv7Xa0lzVJ912QHtWtTjLGrrlYKxVRUqxkVPLhfpwvFH_5kBvVB0_MsOMJnNwRxxxSaUOGGrYLTmd6B70kgkjP1kSN_2963fqCKDhIqG7rgpmuPkExRvfdA1xKSxpyEhFaT5v2GCYOx6tr0jaFzgcRZRKYPrv2GdMXNRy1YiB1oK0MdhDoucFUzkAjmoSzSfloq3mSeOPecxEnFBl36GB23exYOySdI8v8FWP_bNUbad6EXL21aWZGT5XGsDuqOfhmKjiDzzbXwWPP5FdstW6l-qQWDL6SjQj2d3YqrZc_HOl-mEY_puI7p_BJEL1lB_D52aXmHUXAhVb9yNzZls",
* "locale":"zh-CN"
* }
*/
console.error(JSON.stringify(requestOptions));
// delete requestOptions["sessionVariable:XS_APPLICATIONUSER"];
var options = _.extend({}, globalOptions, requestOptions);
hdbext.createConnection(options, function (err, client) {
if (err) {
err.status = 500;
console.error(JSON.stringify(err));
return next(err);
}
req.db = client;
var end = res.end;
res.end = function () {
var resEndArgs = arguments;
debug('Cleanup triggered');
req.db.close(function (err) {
if (err) {
debug('Error while closing connection.', err);
}
delete req.db;
res.end = end;
res.end.apply(res, resEndArgs);
});
};
next();
});
};
}
this.app.use(middleware(xsenv.getServices({hana: {tag: "hana"}}).hana));
所以如果要正常运行，可以在创建 HANA Connection 前把 requestOptions 中的 sessionVariable:XS_APPLICATIONUSER 删掉。
但是这只是模拟 @sap/hdbext 库中的代码，实际上我们不能更改这段代码。那么实际上可以把初始化 HANA DB 的 Middleware 放在初始化 JWT A 之前就可以解决这个问题
// Initialize HDB Middleware before initialize passport authentication
this.app.use(hdbext.middleware(xsenv.getServices({hana: {tag: "hana"}}).hana));
// Initialize JWT authentication
const services = xsenv.getServices({ uaa:'my-xsuaa' });
passport.use(new JWTStrategy(services.uaa));
this.app.use(passport.initialize());
this.app.use(passport.authenticate('JWT', { session: false }));
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