new x/errors package to handle HTTP wire errors

_examples/routing/http-wire-errors/main.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"github.com/kataras/iris/v12"
+	// IMPORTANT, import this sub-package.
+	// Note tht it does NOT break compatibility with the
+	// standard "errors" package as the New,
+	// Is, As, Unwrap functions are aliases to the standard package.
+	"github.com/kataras/iris/v12/x/errors"
+)
+
+// Optionally, register custom error codes.
+//
+// The default list of error code names:
+// errors.Cancelled
+// errors.Unknown
+// errors.InvalidArgument
+// errors.DeadlineExceeded
+// errors.NotFound
+// errors.AlreadyExists
+// errors.PermissionDenied
+// errors.Unauthenticated
+// errors.ResourceExhausted
+// errors.FailedPrecondition
+// errors.Aborted
+// errors.OutOfRange
+// errors.Unimplemented
+// errors.Internal
+// errors.Unavailable
+// errors.DataLoss
+var (
+	Custom = errors.E("CUSTOM_CANONICAL_ERROR_NAME", iris.StatusBadRequest)
+)
+
+func main() {
+	app := iris.New()
+
+	// Custom error code name.
+	app.Get("/custom", fireCustomErrorCodeName)
+
+	// Send a simple 400 request with message and an error
+	// or with more details and data.
+	app.Post("/invalid_argument", fireInvalidArgument)
+
+	// Compatibility with the iris.Problem type (and any other custom type).
+	app.Get("/problem", fireErrorWithProblem)
+
+	app.Listen(":8080")
+}
+
+func fireCustomErrorCodeName(ctx iris.Context) {
+	Custom.Details(ctx, "message", "details with arguments: %s", "an argument")
+}
+
+func fireInvalidArgument(ctx iris.Context) {
+	var req = struct {
+		Username string `json:"username"`
+	}{}
+	if err := ctx.ReadJSON(&req); err != nil {
+		errors.InvalidArgument.Err(ctx, err)
+		return
+	}
+
+	ctx.WriteString(req.Username)
+
+	// Other examples: errors.InvalidArgument/NotFound/Internal and e.t.c.
+	// .Message(ctx, "message %s", "optional argument")
+	// .Details(ctx, "message", "details %s", "optional details argument")
+	// .Data(ctx, "message", anyTypeOfValue)
+	// .DataWithDetails(ctx, "unable to read the body", "malformed json", iris.Map{"custom": "data of any type"})
+	// .Log(ctx, "message %s", "optional argument")
+	// .LogErr(ctx, err)
+}
+
+func fireErrorWithProblem(ctx iris.Context) {
+	myCondition := true
+	if myCondition {
+		problem := iris.NewProblem().
+			// The type URI, if relative it automatically convert to absolute.
+			Type("/product-error").
+			// The title, if empty then it gets it from the status code.
+			Title("Product validation problem").
+			// Any optional details.
+			Detail("details about the product error").
+			// The status error code of the problem, can be optional here.
+			// Status(iris.StatusBadRequest).
+			// Any custom key-value pair.
+			Key("product_name", "the product name")
+
+		errors.InvalidArgument.Data(ctx, "unable to process the request", problem)
+		return
+
+		/* Prints to the client:
+		{
+		  "http_error_code": {
+		    "canonical_name": "INVALID_ARGUMENT",
+		    "status": 400
+		  },
+		  "message": "unable to process the request",
+		  "data": {
+		    "detail": "details about the product error",
+		    "product_name": "the product name",
+		    "title": "Product validation problem",
+		    "type": "/product-error"
+		  }
+		}
+		*/
+	}
+
+}