add url query params chapter

Home.md

@@ -20,6 +20,7 @@ This wiki is the main source of documentation for **developers** working with (o
     * [[Override Context|Routing-override-context]]
 * [[API Versioning]]
 * [[Request Authentication]]
+* [[URL Query Parameters]]
 * [[File Server]]
 * [[View]]
 * [[Dependency Injection|dependency-injection]]

URL-query-parameters.md

@@ -0,0 +1,65 @@
+The Iris Context has two methods that returns the `net/http` standard `http.ResponseWriter` and `http.Request` as we mention in the previous chapters.
+
+- `Context.Request()`
+- `Context.ResponseWriter()`
+
+However except the unique Iris features and helpers that Iris Context offers, for easier development, we provide some wrappers of existing `net/http` capabilities as well.
+
+This is the full list of methods that can help you with URL query string.
+
+```go
+// URLParam returns true if the url parameter exists, otherwise false.
+URLParamExists(name string) bool
+// URLParamDefault returns the get parameter from a request,
+// if not found then "def" is returned.
+URLParamDefault(name string, def string) string
+// URLParam returns the get parameter from a request, if any.
+URLParam(name string) string
+// URLParamTrim returns the url query parameter with trailing white spaces removed from a request.
+URLParamTrim(name string) string
+// URLParamTrim returns the escaped url query parameter from a request.
+URLParamEscape(name string) string
+// URLParamInt returns the url query parameter as int value from a request,
+// returns -1 and an error if parse failed.
+URLParamInt(name string) (int, error)
+// URLParamIntDefault returns the url query parameter as int value from a request,
+// if not found or parse failed then "def" is returned.
+URLParamIntDefault(name string, def int) int
+// URLParamInt32Default returns the url query parameter as int32 value from a request,
+// if not found or parse failed then "def" is returned.
+URLParamInt32Default(name string, def int32) int32
+// URLParamInt64 returns the url query parameter as int64 value from a request,
+// returns -1 and an error if parse failed.
+URLParamInt64(name string) (int64, error)
+// URLParamInt64Default returns the url query parameter as int64 value from a request,
+// if not found or parse failed then "def" is returned.
+URLParamInt64Default(name string, def int64) int64
+// URLParamFloat64 returns the url query parameter as float64 value from a request,
+// returns -1 and an error if parse failed.
+URLParamFloat64(name string) (float64, error)
+// URLParamFloat64Default returns the url query parameter as float64 value from a request,
+// if not found or parse failed then "def" is returned.
+URLParamFloat64Default(name string, def float64) float64
+// URLParamBool returns the url query parameter as boolean value from a request,
+// returns an error if parse failed or not found.
+URLParamBool(name string) (bool, error)
+// URLParams returns a map of GET query parameters separated by comma if more than one
+// it returns an empty map if nothing found.
+URLParams() map[string]string
+```
+
+Query string parameters are parsed using the existing underlying request object.
+The request responds to a url matching: _/welcome?firstname=Jane&lastname=Doe_.
+
+- `ctx.URLParam("lastname")` == `ctx.Request().URL.Query().Get("lastname")`
+
+Example Code:
+
+```go
+    app.Get("/welcome", func(ctx iris.Context) {
+        firstname := ctx.URLParamDefault("firstname", "Guest")
+        lastname := ctx.URLParam("lastname") 
+
+        ctx.Writef("Hello %s %s", firstname, lastname)
+    })
+```

_Sidebar.md

@@ -15,6 +15,7 @@
     * [[Override Context|Routing-override-context]]
 * [[API Versioning]]
 * [[Request Authentication]]
+* [[URL Query Parameters]]
 * [[File Server]]
 * [[View]]
 * [[Dependency Injection|dependency-injection]]