Client-Server WASM-Application In C#, TypeScript And Transact-SQL

FEATURES OF THE WORK
— Pseudo-ORM helpers are used in C# for explicit manual mapping from/to SQL;
— Automated error handling is implemented in SPA (unified behaviour for unexpected exception at the top);
— Quasi-blocking pseudo-synchronous UI is probed in browser in SPA;
— Binary independent Client-Server integration is applied, on base of C# source-code files;
— Through error reporting is available (explicit message + error GUID), from SQL Server to SPA-Client;
— Unified communication with automatic JWT request/update-token(s) renovation is embedded;
— Automation of JSON/C# null-checkings is introduced (with back-packing trick on client-side);
— SQL-File Technology is demonstrated inside the Work — translation from SQL-files to database objects;
— Many other interesting things are present in the Work.

Idea of Client-Server.WEB

The idea is to create reusable skeleton for Web-application simultaneously on both client and server sides, including also some support at database level. This idea also may be named simply as Web-application engine. Such an engine is build in several languages which are normally the same that are used in user application code. (Let us shortly reference to this idea as CSWEB.)

BookRegistry application

I would like to represent to you a little but able-to-work sample program which is based on above mentioned app.skeleton — BookRegistry application in Blazor-WASM, with presence of library-level code and user code in three languages: C#, TypeScript and Transact-SQL. (User interface markup is in HTML/CSS.)

The program demonstrates some operations of simple tool (Web-application), which is intended to support following two things: (I) book selection from database by different parameters, and also (II) editing of book registry. Authorized user may: (1) correct book-record, (2) add new book into book-registry (database), and (3) to delete unnecessary book-record. It’s simple itself (not much user code), but it is strongly cooperated with the engine (skeleton). This construction (engine+app.) provides certain unification into UI and into user app. behaviour. Simplified preuso-synchronous approach for UI-interaction is used in this SPA like somewhere in classic desktop UI (but this is not very restrictive). The program is provided with so-called Magistral layout for SPA performed in a special manner, so as if it is embedded at browser level. This layout is intended to supplement a lack of some important user accessors to UI (that are: vertical side-bar inside application page — with top/bottom scrolling, content selection button, operation escape-unblock, intentional reloading of virtual-page etc.) and also supports so-called Foreground UI-operation (with corresponding visual indication of performing action). Magistral layout is interesting thing which is potentially useful in terms of its general application. It is implemented in TypeScript and it has corresponding simple API for C# (WASM DLL).

Handicraft programming style

Handicraft approach to program development (so-called “handicraft programming”) implies, that somebody maintains or controls a part of system-like code and this significant part of auxiliary and/or low-level code in the application may be kept in hands of one or more individual developers. Non-trivial organization on base of modules (DLLs and not only) is inherent feature of such handicraft programming, as well as a tendency to strong fractional division of program text into numerous source files grouped into subfolders (instead of working with kilometer-long files of code). Handicraft-coding style is good suitable for building of somebody’s own AFX (Application Framework Extension) — your own small auxiliary framework and/or collection of simple general helpers for different purposes. In other words all this may be denoted as User Runtime Extensions (let us name it as URX).

Client-Server WASM-app. skeleton is built with help of DotNetHelpers libraries — set of modules: “CommonHelpers.*.dll” (general purpose libs). DotNetHelpers library set is part of Handicraft-SDK.

Client-Server Web-engine and the application

BookRegistry application together with all its libraries and auxiliaries, all this is standing directly on three imperative languages and without intensive usage of something high-level — as in Web-client so as at server-side. For instance, Bootstrap framework is used superficially (mainly for decorations of different kinds). The server which is in C# (in ASP.NET-Core) operates with database with help of extremely lightweight ORM to SP and queries which is implemented in DotNetHelpers. (This construction sits on ADO.NET-Core.)

Both parts of the program Client & Server are in C# and this is determinative here. For the sake of unified Client-Server interoperation special C#-classes are introduced (as base exchanging structures for data-models). Normally user code does not use JSON-features (C# attributes) intensively. Instead, all declarations of data exchange are specified mainly in pure C# language, which has priority over JSON (in this approach). Conditional compilation is used extensively however for declaration of C# exchangeable objects and in some implementations (code-files). Such non-trivial declaration is used in order to represent exchange data-model in one single place, so that this description takes effect for the both sides (client/server), but with some differences in behaviour at sides of the server and the client.

Also, there is a lot interesting concerning to error handling, especially in client-side. For example, error page is implemented in WASM-Blazor. Special technique is used when dealing with possible exceptions. See source code of BookRegistry.Client subproject (in corresponding BookRegistry app. download from supporting site).

Experimental way

My approach is not simple of cause, but looking to user written code as onto separate part from one side and onto CSWEB-engine so as it is framework extension or base skeleton (which does already exist) from the other side, the program then doesn’t seem so complex (at least in its user part). Also, some reorganization may improve the situation concerning to clarity and accessibility. (This is experimental application.)

Blog publisher

Sergei Y.Kitáev
Handicraft-CODE domain author
https://handicraft.remelias.ru/

CSWEB introductory article at C# Corner

Client-Server WASM-Application In C#, TypeScript And Transact-SQL
C# Corner / Technologies / Blazor (Developer Community Web-Site)