Web back-end development based on Gin framework (3): Get queryString parameters

tips:

• To get queryString we often use GET request
• go mod tidy It can analyze the third-party packages that the code depends on, and then record these in go.mod.

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For example: to get Yang Chaoyue in the query field:
http://127.0.0.1:9090/web?query=杨超越

Method 1: Query

 package main

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func main() {
    r := gin.Default()
    r.GET("/web", func(c *gin.Context) {
        //这里要获取浏览器那边发请求携带的query string参数
        name := c.Query("query")
        c.JSON(http.StatusOK, gin.H{
            "name": name,
        })
    })
    r.Run(":9090")
}

The test results are as follows:

Method 2: DefaultQuery

This is actually similar to method 1, the difference is that if no data is queried, you can use the set default data:

 package main

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func main() {
    r := gin.Default()
    r.GET("/web", func(c *gin.Context) {
        //这里要获取浏览器那边发请求携带的query string参数
        //name := c.Query("query")
        name := c.DefaultQuery("query", "someone")
        c.JSON(http.StatusOK, gin.H{
            "name": name,
        })
    })

    r.Run(":9090")
}

The test results are as follows:

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Method 3: GetQuery

This function has two return values, which is actually an extra bool value. If the parameter cannot be reached, the second one returns false:

 package main

import (
    "github.com/gin-gonic/gin"
    "net/http"
)

func main() {
    r := gin.Default()
    r.GET("/web", func(c *gin.Context) {
        //这里要获取浏览器那边发请求携带的query string参数
        //name := c.Query("query")
        //name := c.DefaultQuery("query", "someone")
        name, ok := c.GetQuery("query")
        if !ok {
            name = "someone"
        }
        c.JSON(http.StatusOK, gin.H{
            "name": name,
        })
    })

    r.Run(":9090")
}

I think the third method is more comprehensive and I prefer to use it. Of course, the other two methods can also be used in suitable scenarios.

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Reference: bilibili