Category: Uncategorized

Create RestAPI with Go & Postgres: Post, Get, PUT, Delete example code

Create Post Api with Go example code

To create a “POST” API in Go, you can use the net/http package that is included in the Go standard library. Here’s an example of how you can create a simple “POST” API that listens on a specific port and responds with “Hello, World!” when a client makes a “POST” request to the endpoint:

package main

import (
	"fmt"
	"net/http"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		if r.Method == http.MethodPost {
			fmt.Fprint(w, "Hello, World!")
			return
		}
		http.Error(w, "Invalid request method", http.StatusBadRequest)
	})

	http.ListenAndServe(":8080", nil)
}

In this example, the http.HandleFunc function is used to register a function that will be called whenever a client makes a request to the root endpoint (“/”). The function checks the request method to see if it is a “POST” request, and if it is, it responds with “Hello, World!”. If the request method is not “POST”, it sends an error response with status code “400 Bad Request”. Finally, the http.ListenAndServe function is used to start the server and listen for incoming requests on port 8080.

Create GET api with go example code

Here is an example of a basic GET API written in Go using the popular Gin web framework:

package main

import (
    "net/http"

    "github.com/gin-gonic/gin"
)

func main() {
    r := gin.Default()

    r.GET("/", func(c *gin.Context) {
        c.JSON(http.StatusOK, gin.H{
            "message": "Hello, World!",
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the root URL (“/”) that responds to GET requests. The route handler is a function that takes a Gin context as its argument. This function sends a JSON response with a message of “Hello, World!” and a status code of 200 OK. Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a GET request to http://localhost:8080/ using any HTTP client.

Create PUT API with Go example code

Here is an example of a basic PUT API written in Go using the popular Gin web framework:

package main

import (
    "net/http"

    "github.com/gin-gonic/gin"
)

func main() {
    r := gin.Default()

    r.PUT("/user/:id", func(c *gin.Context) {
        // Get the ID from the URL parameters
        id := c.Param("id")

        // Bind the request body to a struct
        var user struct {
            Name string `json:"name" binding:"required"`
            Age  int    `json:"age" binding:"required"`
        }
        if err := c.ShouldBindJSON(&user); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }

        // Update the user in the database
        // ...

        c.JSON(http.StatusOK, gin.H{
            "message": "User updated successfully",
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the URL path /user/:id that responds to PUT requests. The :id in the route path is a URL parameter.
The route handler is a function that takes a Gin context as its argument. This function first extracts the “id” from the URL parameters, then binds the request body to a struct, in this case the struct is user which contains Name and Age field.
Then it checks if there is any error from the binding process, if there is, it will return a Bad Request with the error message.
If no error, it will update the user in the database (this part is left to you to implement) and then sends a JSON response with a message of “User updated successfully” and a status code of 200 OK. Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a PUT request to http://localhost:8080/user/ using any HTTP client with json payload of the user such as {“name”:”John”,”age”:25}

Create Delete RestAPI with Go example code

Here is an example of a basic DELETE REST API written in Go using the popular Gin web framework:

package main

import (
    "net/http"

    "github.com/gin-gonic/gin"
)

func main() {
    r := gin.Default()

    r.DELETE("/user/:id", func(c *gin.Context) {
        // Get the ID from the URL parameters
        id := c.Param("id")

        // Delete the user from the database
        // ...

        c.JSON(http.StatusOK, gin.H{
            "message": "User deleted successfully",
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the URL path /user/:id that responds to DELETE requests. The :id in the route path is a URL parameter.
The route handler is a function that takes a Gin context as its argument. This function first extracts the “id” from the URL parameters, then deletes the user from the database (this part is left to you to implement) and then sends a JSON response with a message of “User deleted successfully” and a status code of 200 OK. Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a DELETE request to http://localhost:8080/user/ using any HTTP client.

Create Post RestAPI with Go and Postgresql example code

Here is an example of a basic POST REST API written in Go using the popular Gin web framework and Postgresql as a database:

package main

import (
    "database/sql"
    "net/http"

    "github.com/gin-gonic/gin"
    _ "github.com/lib/pq"
)

func main() {
    db, err := sql.Open("postgres", "postgres://user:password@host/dbname")
    if err != nil {
        panic(err)
    }
    defer db.Close()

    r := gin.Default()

    r.POST("/user", func(c *gin.Context) {
        // Bind the request body to a struct
        var user struct {
            Name string `json:"name" binding:"required"`
            Age  int    `json:"age" binding:"required"`
        }
        if err := c.ShouldBindJSON(&user); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }

        // Insert the user into the database
        _, err := db.Exec("INSERT INTO users (name, age) VALUES ($1, $2)", user.Name, user.Age)
        if err != nil {
            c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
            return
        }

        c.JSON(http.StatusCreated, gin.H{
            "message": "User created successfully",
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the URL path /user that responds to POST requests.
The route handler is a function that takes a Gin context as its argument. This function first binds the request body to a struct, in this case the struct is user which contains Name and Age field.
Then it checks if there is any error from the binding process, if there is, it will return a Bad Request with the error message.
If no error, it will insert the user into the Postgresql database by executing the SQL statement INSERT INTO users (name, age) VALUES ($1, $2) using the user’s name and age as the parameters and then sends a JSON response with a message of “User created successfully” and a status code of 201 Created.
It also checks if there is any error while executing the query, if so it will return a status code of 500 Internal Server Error with the error message.
Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a POST request to http://localhost:8080/user using any HTTP client with json payload of the user such as {“name”:”John”,”age”:25}

Please note that the database connection string is an example and you need to change it to match your database credentials and settings.
Also, it is important to note that you need to have the “github.com/lib/pq” package installed and imported in order to use postgres as a database with Go.
Also, it is assumed that you have the necessary table created in the database and ready to use.

Create Get RestAPI with Go and Postgresql example code

Here is an example of a basic GET REST API written in Go using the popular Gin web framework and Postgresql as a database:

package main

import (
    "database/sql"
    "net/http"

    "github.com/gin-gonic/gin"
    _ "github.com/lib/pq"
)

func main() {
    db, err := sql.Open("postgres", "postgres://user:password@host/dbname")
    if err != nil {
        panic(err)
    }
    defer db.Close()

    r := gin.Default()

    r.GET("/user/:id", func(c *gin.Context) {
        // Get the ID from the URL parameters
        id := c.Param("id")

        // Get the user from the database
        var user struct {
            Name string
            Age  int
        }
        err := db.QueryRow("SELECT name, age FROM users WHERE id = $1", id).Scan(&user.Name, &user.Age)
        if err != nil {
            c.JSON(http.StatusNotFound, gin.H{"error": "User not found"})
            return
        }

        c.JSON(http.StatusOK, gin.H{
            "user": user,
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the URL path /user/:id that responds to GET requests. The :id in the route path is a URL parameter.
The route handler is a function that takes a Gin context as its argument. This function first extracts the “id” from the URL parameters, then it queries the Postgresql database for user with the corresponding id by executing the SQL statement SELECT name, age FROM users WHERE id = $1 and scan the result into user struct.
Then it checks if there is any error from the query, if there is and the error is not found, it will return a Not Found with the error message.
If no error, it will send a JSON response with the user data and a status code of 200 OK.
Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a GET request to http://localhost:8080/user/ using any HTTP client.
Please note that the database connection string is an example and you need to change it to match your database credentials and settings.
Also, it is important to note that you need to have the “github.com/lib/pq” package installed and imported in order to use postgres as a database with Go.
Also, it is assumed that you have the necessary table created in the database and ready to use.

Create Put RestAPI with Go and Postgresql example code

Here is an example of a basic PUT REST API written in Go using the popular Gin web framework and Postgresql as a database:

package main

import (
    "database/sql"
    "net/http"

    "github.com/gin-gonic/gin"
    _ "github.com/lib/pq"
)

func main() {
    db, err := sql.Open("postgres", "postgres://user:password@host/dbname")
    if err != nil {
        panic(err)
    }
    defer db.Close()

    r := gin.Default()

    r.PUT("/user/:id", func(c *gin.Context) {
        // Get the ID from the URL parameters
        id := c.Param("id")

        // Bind the request body to a struct
        var user struct {
            Name string `json:"name" binding:"required"`
            Age  int    `json:"age" binding:"required"`
        }
        if err := c.ShouldBindJSON(&user); err != nil {
            c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
            return
        }

        // Update the user in the database
        _, err := db.Exec("UPDATE users SET name = $1, age = $2 WHERE id = $3", user.Name, user.Age, id)
        if err != nil {
            c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
            return
        }

        c.JSON(http.StatusOK, gin.H{
            "message": "User updated successfully",
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the URL path /user/:id that responds to PUT requests. The :id in the route path is a URL parameter.
The route handler is a function that takes a Gin context as its argument. This function first extracts the “id” from the URL parameters, then binds the request body to a struct, in this case the struct is user which contains Name and Age field.
Then it checks if there is any error from the binding process, if there is, it will return a Bad Request with the error message.
If no error, it will update the user in the Postgresql database by executing the SQL statement UPDATE users SET name = $1, age = $2 WHERE id = $3 using the user’s name, age and id as the parameters and then sends a JSON response with a message of “User updated successfully” and a status code of 200 OK.
It also checks if there is any error while executing the query, if so it will return a status code of 500 Internal Server Error with the error message.
Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a PUT request to http://localhost:8080/user/ using any HTTP client with json payload of the user such as {“name”:”John”,”age”:25}
Please note that the database connection string is an example and you need to change it to match your database credentials and settings.

Create Delete RestAPI with Go and Postgresql example code

Here is an example of a basic DELETE REST API written in Go using the popular Gin web framework and Postgresql as a database:

package main

import (
    "database/sql"
    "net/http"

    "github.com/gin-gonic/gin"
    _ "github.com/lib/pq"
)

func main() {
    db, err := sql.Open("postgres", "postgres://user:password@host/dbname")
    if err != nil {
        panic(err)
    }
    defer db.Close()

    r := gin.Default()

    r.DELETE("/user/:id", func(c *gin.Context) {
        // Get the ID from the URL parameters
        id := c.Param("id")

        // Delete the user from the database
        _, err := db.Exec("DELETE FROM users WHERE id = $1", id)
        if err != nil {
            c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
            return
        }

        c.JSON(http.StatusOK, gin.H{
            "message": "User deleted successfully",
        })
    })

    r.Run() // listen and serve on 0.0.0.0:8080
}

This code creates a new Gin router and sets up a route for the URL path /user/:id that responds to DELETE requests. The :id in the route path is a URL parameter.
The route handler is a function that takes a Gin context as its argument. This function first extracts the “id” from the URL parameters, then deletes the user from the Postgresql database by executing the SQL statement DELETE FROM users WHERE id = $1 using the user’s id as the parameter and then sends a JSON response with a message of “User deleted successfully” and a status code of 200 OK.
It also checks if there is any error while executing the query, if so it will return a status code of 500 Internal Server Error with the error message.
Finally, the router is started by calling the Run() method.

You would run this code by running go run main.go, and then making a DELETE request to http://localhost:8080/user/ using any HTTP client.

How to write unit-testcase for Go RestAPI

Unit testing in Go is typically done using the built-in testing package. You can use this package to create unit tests for your REST API by writing test functions that make HTTP requests to your API and assert that the responses are as expected.

Here’s an example of how you might write a unit test for a GET endpoint that retrieves a user by ID:

package main

import (
    "net/http"
    "net/http/httptest"
    "testing"

    "github.com/gin-gonic/gin"
)

func TestGetUser(t *testing.T) {
    // Set up the router and a test server
    router := gin.Default()
    router.GET("/user/:id", getUser)
    w := httptest.NewRecorder()
    req, _ := http.NewRequest("GET", "/user/1", nil)
    router.ServeHTTP(w, req)

    // Assert that the response has the expected status code and body
    if w.Code != http.StatusOK {
        t.Errorf("Expected status code %d, got %d", http.StatusOK, w.Code)
    }
    expectedBody := `{"user":{"name":"John","age":25}}`
    if w.Body.String() != expectedBody {
        t.Errorf("Expected body %s, got %s", expectedBody, w.Body.String())
    }
}

This test function creates a new Gin router, sets up a route for the /user/:id path that calls the getUser function, and then creates a test server using httptest.NewRecorder().
It creates an HTTP GET request to the endpoint and serves the request to the test server.
The test function uses the testing package’s Errorf function to check that the response has the expected status code (200 OK) and body ({“user”:{“name”:”John”,”age”:25}}).

To run this test, you can use the command go test in your project’s directory. The test function name should be in the format Test* to be recognized as a unit test.

You can also use testing frameworks like testify which provides a lot of useful testing utility functions like assert and require which makes it more readable and easy to use for testing.

It’s also important to note that you may want to consider testing your database interactions in isolation, by using a library like sqlmock which allows you to mock and test your database interactions without hitting an actual database.

How to Integrate Data-dog with Spring example

Datadog is a cloud-based monitoring and analytics platform for modern cloud environments. It provides real-time visibility into the performance, health, and security of your infrastructure, applications, and logs. With Datadog, you can monitor your systems, track errors and exceptions, and get alerted when issues arise. You can also use the platform to investigate and troubleshoot problems, optimize your application performance, and ensure the security and compliance of your systems. Datadog integrates with a wide range of technologies and services, including cloud providers, databases, servers, containers, and more.

How to Integrate Data-dog with Spring example

To add tracing to a Spring application using Datadog, you will need to include the Datadog Java library in your application and use it to instrument your code. This will allow you to send trace data from your application to the Datadog Agent, which will then forward it to the Datadog APM (Application Performance Monitoring) platform.

Here’s a high-level overview of the steps you can follow to add tracing to a Spring application using Datadog:

1. Include the Datadog Java library in your application. You can do this using Maven by adding the following dependency to your pom.xml file:


  com.datadog
  dd-java-agent
  0.46.0

2. Instrument your code with Datadog tracing. The Datadog Java library provides a Tracer class that you can use to add trace spans to your code. A trace span represents a unit of work in your application, such as a database query or a remote service call. You can create a span using the Tracer.startSpan() method and specify a name for the span and any relevant tags. When the span is complete, you can stop it using the Tracer.finishSpan() method.

3. (Optional) Enable automatic instrumentation for common libraries and frameworks. The Datadog Java library includes automatic instrumentation for various libraries and frameworks, such as Spring, Hibernate, and JDBC. You can enable this instrumentation by adding the relevant dependencies to your application and including the necessary configuration in your application’s application.properties file.

4. Deploy your application and start sending trace data to Datadog. Once you have instrumented your code and enabled automatic instrumentation (if desired), you can deploy your application and start sending trace data to the Datadog Agent. The trace data will then be forwarded to the Datadog APM platform, where you can view and analyze it.

DataDog can Automatic Instrumentation with SpringBoot RestAPI

Yes, DataDog’s Java library includes automatic instrumentation for Spring Boot REST APIs. This means that you can use the library to automatically capture trace data for your REST API without having to manually instrument your code.

To enable automatic instrumentation for your Spring Boot REST API, you will need to include the Datadog Java library and the Spring Boot starter in your application, and configure the library to enable automatic instrumentation.

Here’s a high-level overview of the steps you can follow to enable automatic instrumentation for a Spring Boot REST API using DataDog:

1. Include the Datadog Java library and the Spring Boot starter in your application. You can do this using Maven by adding the following dependencies to your pom.xml file:


  com.datadog
  dd-java-agent
  0.46.0


  com.datadog.tracing
  dd-trace-spring-boot-starter
  0.46.0

2. Enable automatic instrumentation in your application’s configuration. You can enable automatic instrumentation by adding the following configuration to your application’s application.properties file:

dd.instrumentation.spring.web.enabled=true

Deploy your application and start capturing trace data. Once you have included the necessary dependencies and enabled automatic instrumentation, you can deploy your application and start capturing trace data for your REST API. The trace data will be sent to the Datadog Agent, which will forward it to the Datadog APM platform.

What is StatsDClient and how to use it?

StatsD is a network daemon that runs on your server and listens for statistics that are sent to it over UDP. It can then forward these statistics to a backend service such as Datadog, Graphite, or InfluxDB for storage and visualization.

The StatsDClient is a Java library that provides a client implementation of the StatsD protocol. You can use the StatsDClient to send custom metrics from your Java application to a StatsD daemon running on your server. The StatsDClient provides a simple interface for sending various types of metrics, such as counters, gauges, and histograms.

Here’s a simple example of how to use the StatsDClient to send a counter metric to a StatsD daemon:

import com.timgroup.statsd.StatsDClient;

// Create a StatsDClient
StatsDClient statsd = new NonBlockingStatsDClient("my_application", "localhost", 8125);

// Increment a counter metric
statsd.incrementCounter("page_views");

// Close the StatsDClient
statsd.stop();

This code creates a new StatsDClient that connects to a StatsD daemon running on localhost at port 8125. It then increments a counter metric called “page_views” and sends it to the daemon. Finally, it closes the StatsDClient.

How to version restapi with springboot

There are several ways to version a REST API using Spring Boot. Here are a few approaches you can consider:

URL path parameter: You can include the version number as a path parameter in the URL of each API endpoint. For example: /api/v1/customers and /api/v2/customers.

Accept header parameter: You can include the version number in the Accept header of the HTTP request. This can be useful if you want to allow the client to specify the version of the API it wants to use.

Custom request header: You can include a custom request header, such as X-API-Version, to specify the version of the API that the client wants to use.

URI suffix: You can include the version number as a suffix in the URI of each API endpoint. For example: /api/customers/v1 and /api/customers/v2.

Regardless of the approach you choose, you will need to implement a request mapping mechanism in your Spring Boot application to route requests to the appropriate version of the API based on the version information provided by the client. You can use the @RequestMapping annotation to specify the version number in the URL path, the Accept header, or a custom request header.

SpringBoot versioning API with URL path parameter example code

Certainly! Here is an example of how you can version a REST API using URL path parameters in Spring Boot:

@RestController
@RequestMapping("/api/{version}/customers")
public class CustomerController {

    @GetMapping
    public List getCustomers(@PathVariable String version) {
        // retrieve customers for the specified version of the API
    }

    @PostMapping
    public Customer createCustomer(@PathVariable String version, @RequestBody Customer customer) {
        // create a customer for the specified version of the API
    }
}

In this example, the @RequestMapping annotation specifies that all API endpoints in the CustomerController class are mapped to URLs that include a version path parameter. The @PathVariable annotation is used to bind the value of the version path parameter to a method parameter.

You can then use the value of the version parameter to determine which version of the API to use. For example, you could have separate implementations of the getCustomers and createCustomer methods for different versions of the API, and use the version parameter to determine which implementation to use.

SpringBoot versioning API with Accept header parameter code example

Sure! Here is an example of how you can version a REST API using the Accept header in Spring Boot:

@RestController
@RequestMapping("/api/customers")
public class CustomerController {

    @GetMapping(headers = "Accept=application/vnd.customers.v1+json")
    public List getCustomersV1() {
        // retrieve customers for version 1 of the API
    }

    @GetMapping(headers = "Accept=application/vnd.customers.v2+json")
    public List getCustomersV2() {
        // retrieve customers for version 2 of the API
    }

    @PostMapping(headers = "Accept=application/vnd.customers.v1+json")
    public Customer createCustomerV1(@RequestBody Customer customer) {
        // create a customer for version 1 of the API
    }

    @PostMapping(headers = "Accept=application/vnd.customers.v2+json")
    public Customer createCustomerV2(@RequestBody Customer customer) {
        // create a customer for version 2 of the API
    }
}

In this example, the @GetMapping and @PostMapping annotations include a headers attribute that specifies the Accept header value that should be used to match the request to a particular API version.

To use this approach, the client would need to include the appropriate Accept header value in the request to specify which version of the API it wants to use. For example, to use version 1 of the API, the client would include the Accept header value application/vnd.customers.v1+json.

SpringBoot versioning API with Custom request header code example

Certainly! Here is an example of how you can version a REST API using a custom request header in Spring Boot:

@RestController
@RequestMapping("/api/customers")
public class CustomerController {

    @GetMapping(headers = "X-API-Version=1")
    public List getCustomersV1() {
        // retrieve customers for version 1 of the API
    }

    @GetMapping(headers = "X-API-Version=2")
    public List getCustomersV2() {
        // retrieve customers for version 2 of the API
    }

    @PostMapping(headers = "X-API-Version=1")
    public Customer createCustomerV1(@RequestBody Customer customer) {
        // create a customer for version 1 of the API
    }

    @PostMapping(headers = "X-API-Version=2")
    public Customer createCustomerV2(@RequestBody Customer customer) {
        // create a customer for version 2 of the API
    }
}

n this example, the @GetMapping and @PostMapping annotations include a headers attribute that specifies the custom request header X-API-Version and its expected value.

To use this approach, the client would need to include the X-API-Version header in the request with the appropriate value to specify which version of the API it wants to use. For example, to use version 1 of the API, the client would include the header X-API-Version: 1.

SpringBoot versioning API with URI suffix code example

Certainly! Here is an example of how you can version a REST API using a URI suffix in Spring Boot:

@RestController
@RequestMapping("/api/customers")
public class CustomerController {

    @GetMapping("/v1")
    public List getCustomersV1() {
        // retrieve customers for version 1 of the API
    }

    @GetMapping("/v2")
    public List getCustomersV2() {
        // retrieve customers for version 2 of the API
    }

    @PostMapping("/v1")
    public Customer createCustomerV1(@RequestBody Customer customer) {
        // create a customer for version 1 of the API
    }

    @PostMapping("/v2")
    public Customer createCustomerV2(@RequestBody Customer customer) {
        // create a customer for version 2 of the API
    }
}

Example code

Certainly! Here is an example of how you can version a REST API using a URI suffix and Spring JPA in Spring Boot with a PostgreSQL database:

@RestController
@RequestMapping("/api/customers")
public class CustomerController {

    @Autowired
    private CustomerRepository customerRepository;

    @GetMapping("/v1")
    public List getCustomersV1() {
        return customerRepository.findByVersion(1);
    }

    @GetMapping("/v2")
    public List getCustomersV2() {
        return customerRepository.findByVersion(2);
    }

    @PostMapping("/v1")
    public Customer createCustomerV1(@RequestBody Customer customer) {
        customer.setVersion(1);
        return customerRepository.save(customer);
    }

    @PostMapping("/v2")
    public Customer createCustomerV2(@RequestBody Customer customer) {
        customer.setVersion(2);
        return customerRepository.save(customer);
    }
}

@Repository
public interface CustomerRepository extends JpaRepository {
    List findByVersion(int version);
}

@Entity
@Table(name = "customers")
public class Customer {
    // ...

    @Column(name = "version")
    private int version;

    // ...

    public int getVersion() {
        return version;
    }

    public void setVersion(int version) {
        this.version = version;
    }
}

In this example, the CustomerController class includes @GetMapping and @PostMapping annotations with URI suffixes that specify the version of the API to be used. The CustomerRepository interface extends JpaRepository and defines a findByVersion method that can be used to retrieve customers for a specific version of the API.

The Customer entity includes a version field that is persisted to the customers table in the PostgreSQL database. The getCustomersV1 and getCustomersV2 methods use the findByVersion method to retrieve customers for the specified version of the API, and the createCustomerV1 and createCustomerV2 methods set the version field of the Customer entity before saving it to the database.

To use this approach, the client would need to include the appropriate URI suffix in the request to specify which version of the API it wants to use. For example, to use version 1 of the API, the client would send a request to /api/customers/v1.

Write a python script to create a regular expression to extract the phone number from a given text

Example 1

Here is a Python script that uses a regular expression to extract a phone number from a given string of text:

import re

def extract_phone_number(text):
    phone_regex = r'\b\d{3}[-.]?\d{3}[-.]?\d{4}\b'
    match = re.search(phone_regex, text)
    if match:
        return match.group()
    return None

text = "Please call me at 555-555-1212 or 555.555.1212"
phone_number = extract_phone_number(text)
print(phone_number)

This script will output the following:

555-555-1212

The regular expression \b\d{3}[-.]?\d{3}[-.]?\d{4}\b is used to match a phone number in the text. The regular expression will match a string of digits that is either 7 or 10 characters long, with an optional hyphen or period as a separator. The \b at the beginning and end of the regular expression indicates that the match should occur at a word boundary.

The re.search() function is used to search for the first occurrence of the regular expression in the text. If a match is found, the match.group() function is used to extract the matched phone number. If no match is found, the function returns None.

Example 2

Here is a Python script that uses the re module to create a regular expression to extract a phone number from a given text string:

import re

def extract_phone_number(text):
    # Create a regular expression pattern to match phone numbers
    pattern = r'\b(\d{3}[-\.\s]??\d{3}[-\.\s]??\d{4}|\(\d{3}\)\s*\d{3}[-\.\s]??\d{4}|\d{3}[-\.\s]??\d{4})\b'
    # Use the `search` function to find the first phone number in the text
    match = re.search(pattern, text)
    if match:
        # Return the matched phone number
        return match.group()
    else:
        # Return None if no phone number was found
        return None

# Test the function
text = "Please call me at 555-555-1212 or (888) 555-1212"
phone_number = extract_phone_number(text)
print(phone_number)  # Outputs: 555-555-1212

Example 3

Here is a Python script that uses a regular expression to extract a phone number from a given text:

import re

# The text to search for a phone number
text = "Please call me at 555-123-4567 or 555-987-6543"

# The regular expression pattern to match a phone number
pattern = r"\d{3}-\d{3}-\d{4}"

# Find all phone numbers in the text using the regular expression pattern
matches = re.findall(pattern, text)

# Print the phone numbers that were found
print(matches)

This script will output the following:

['555-123-4567', '555-987-6543']

The regular expression pattern \d{3}-\d{3}-\d{4} matches strings that consist of 3 digits, followed by a dash, followed by 3 digits, followed by a dash, followed by 4 digits. This pattern will match phone numbers in the common format of 555-555-5555.

You can use the findall function from the re module to search for all occurrences of a pattern in a string. The findall function returns a list of all the matches.

Elixir create RestApi Model: One to one example: PostgreSQL + MySQL + MongoDB

Example 1: Exilir + PostgreSQL: One-to-One

Here’s an example of how you might create a REST API in Elixir that uses a PostgreSQL database and models a one-to-one relationship between two entities, using the Plug and Ecto libraries:

defmodule MyApi do
  use Plug.Router
  use Ecto.Repo, otp_app: :my_app

  plug :match
  plug :dispatch

  get "/users/:user_id/profile" do
    user_id = Integer.parse(conn.params["user_id"])
    user = Repo.get(User, user_id)
    profile = Repo.get(Profile, user.profile_id)
    conn
    |> put_resp_content_type("application/json")
    |> send_resp(200, Poison.encode!(%{user: user, profile: profile}))
  end
end

This defines a single endpoint, GET /users/:user_id/profile, which retrieves a user and their associated profile from the users and profiles tables in the database, respectively, and returns them as a JSON object. The user_id is passed as a URL parameter.

To run this API, you’ll need to set up a database connection using the Ecto library. Here’s an example of how you might do this in your config.exs file:

config :my_app, MyApi.Repo,
  adapter: Ecto.Adapters.Postgres,
  database: "my_database",
  username: "postgres",
  password: "postgres",
  hostname: "localhost"

You can then use the Plug.Adapters.Cowboy adapter to run the API as a standalone web server:

Plug.Adapters.Cowboy.http MyApi, []

This is just a very simple example, but you can use the Plug and Ecto libraries to build more complex APIs with multiple endpoints, various HTTP methods, and more advanced database queries.

For more information, you can check out the documentation for the Plug and Ecto libraries:

Plug: https://hexdocs.pm/plug/readme.html
Ecto: https://hexdocs.pm/ecto/readme.html

Example 2: Elixir MySQL One-to-One RestAPI

Here’s an example of how you might create a REST API in Elixir that uses a MySQL database and models a one-to-one relationship between two entities, using the Plug and Ecto libraries:

defmodule MyApi do
  use Plug.Router
  use Ecto.Repo, otp_app: :my_app

  plug :match
  plug :dispatch

  get "/users/:user_id/profile" do
    user_id = Integer.parse(conn.params["user_id"])
    user = Repo.get(User, user_id)
    profile = Repo.get(Profile, user.profile_id)
    conn
    |> put_resp_content_type("application/json")
    |> send_resp(200, Poison.encode!(%{user: user, profile: profile}))
  end
end

This defines a single endpoint, GET /users/:user_id/profile, which retrieves a user and their associated profile from the users and profiles tables in the database, respectively, and returns them as a JSON object. The user_id is passed as a URL parameter.

To run this API, you’ll need to set up a database connection using the Ecto library. Here’s an example of how you might do this in your config.exs file:

config :my_app, MyApi.Repo,
  adapter: Ecto.Adapters.MySQL,
  database: "my_database",
  username: "root",
  password: "root",
  hostname: "localhost"

You’ll also need to install the mysql_ecto library, which provides the MySQL adapter for Ecto. To do this, add mysql_ecto to your list of dependencies in your mix.exs file:

defp deps do
  [
    {:mysql_ecto, "~> 2.0"}
  ]
end

Then run mix deps.get to install the dependencies.

You can then use the Plug.Adapters.Cowboy adapter to run the API as a standalone web server:

Plug.Adapters.Cowboy.http MyApi, []

Example 3: Elixir + MongoDB + One-to-One

Here’s an example of how you might create a REST API in Elixir that uses a MongoDB database and models a one-to-one relationship between two entities, using the Plug and Mongo libraries:

defmodule MyApi do
  use Plug.Router
  use Mongo.Connection

  plug :match
  plug :dispatch

  get "/users/:user_id/profile" do
    user_id = conn.params["user_id"]
    user = Mongo.find_one("users", %{"_id" => user_id})
    profile = Mongo.find_one("profiles", %{"user_id" => user_id})
    conn
    |> put_resp_content_type("application/json")
    |> send_resp(200, Poison.encode!(%{user: user, profile: profile}))
  end
end

This defines a single endpoint, GET /users/:user_id/profile, which retrieves a user and their associated profile from the users and profiles collections in the database, respectively, and returns them as a JSON object. The user_id is passed as a URL parameter.

To run this API, you’ll need to set up a database connection using the Mongo library. Here’s an example of how you might do this in your config.exs file:

config :my_app, MyApi.Mongo,
  hostname: "localhost",
  database: "my_database"

You’ll also need to install the mongodb library, which provides the MongoDB driver for Elixir. To do this, add `mongod