My learning diary

Read Sheets in Java

If you need to programmatically read a Google spreadsheet in Java, the quickstart guide describes a class that does configuration, scoping and reading all in one. However, if you use Spring Boot, you would want to split it into configuration and service layers: // build.gradle ... dependencies { ... compile ('') compile ('') ... } ... // Spring Boot // Your config layer should contain the Sheets bean: // Copied from: https://stackoverflow.

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File Upload to Spring Boot

Implementing file uploads through GraphQL was something I never managed to succeed in. Got embroiled in type incompatibilities. And eventually, I gave up and implemented a separate but simple API endpoint just for file uploads. So here’s the design: The user clicks “Submit”. The files get uploaded first. Upon upload, the server returns IDs. And the rest of the form data plus the returned IDs are sent to the GraphQL endpoint.

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Spring Boot Interceptors

A neat trick to log HTTP requests and responses in a Spring Boot project is through interceptors. To log requests and responses between the client and the server, I use the HandlerInterceptor (Introduction to Spring MVC HandlerInterceptor). To create this interceptor, simply extend the HandlerInterceptor interface. By overriding the various methods available, you can intercept the request and/or response at different points of time. For example, preHandle is executed before the request is executed (i.

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Numerical IDs in MongoDB

Auto-generated IDs in MongoDB are “strange” strings. I quote “strange” because they are actually derived not out of nowhere despite looking like they had nothing to do with anything. But to users, these IDs are strange. I had a collection of documents with a name property. Originally, name was annotated with @Id. But it meant that I could not change the value of name. name was also annotated with regex validation (@Pattern(.

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Abstract classes and AOP

I wanted to avoid writing boilerplate code for CRUD in Spring Boot. But I failed - I could not make my child aspect get along with my child controller. Before adopting AOP, I had an abstract controller which the child controller inherited. CRUD worked well and I no longer needed to repeat the code for simple CRUD anymore. I was happy. // MyAbstractController public abstract class MyAbstractController<T extends UniversalModel> { private final .

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