Merge pull request #6 from kolesa-team/default-values

Allows to get the default value for the expression

README.md

@@ -290,6 +290,7 @@ Request data:
  - storage.SetValue(key, value) - stores a value corresponding to a given key and returns the value. This is useful if you have some entities requested by both id and name, so that you can store the mapping between than and later retrieve it. You can check the samples in [storage](config/persistence/storage/) folder
  - storage.GetValue(key) - returns the value corresponding to the given key
  - dynamic.Calc(expression) - returns the result of a mathematical or logical expression
+ - default.Get(value, default) - returns the first value if it's not empty or the default second
 
 > Regex: The regex should contain a group named **value** which will be matched and its value will be returned. E.g. if we want to match the id from this url **`/your/path/4`** the regex should look like **`/your/path/(?P<value>\\d+)`**. Note that in *golang* the named regex group match need to contain a **P** symbol after the question mark. The regex should be prefixed either with **request.url.**, **request.body.** or **response.body.** considering your input. When setting the Persist.Collection field the regex can match multiple records from it's input, which is useful for cases like [users-delete-passingids.json](config/persistence/users-delete-passingids.json)
 

config/getDefault.json

@@ -0,0 +1,11 @@
+{
+  "description": "Handle default values. Returns the second (default) value if the first on is empty",
+  "request": {
+    "method": "GET",
+    "path": "/get-default-value"
+  },
+  "response": {
+    "statusCode": 200,
+    "body": "{{ default.Get(cat, dog) }}"
+  }
+}

vars/default_values_filter.go

@@ -0,0 +1,60 @@
+package vars
+
+import (
+	"github.com/kolesa-team/http-api-mock/definition"
+	"github.com/kolesa-team/http-api-mock/persist"
+	"github.com/kolesa-team/http-api-mock/utils"
+	"regexp"
+	"strings"
+)
+
+type DefaultValuesFilter struct {
+	Engines     *persist.PersistEngineBag
+	RegexHelper utils.RegexHelper
+}
+
+func (dvf DefaultValuesFilter) Fill(_ *definition.Mock, input string, _ bool) string {
+	r := regexp.MustCompile(`\{\{\s*default\.([^{]+?)\s*}}`)
+	if r.MatchString(input) {
+		input = dvf.Process(r, input)
+	}
+
+	return input
+}
+
+func (dvf DefaultValuesFilter) Process(r *regexp.Regexp, input string) string {
+	return r.ReplaceAllStringFunc(input, func(raw string) string {
+		found := false
+		s := ""
+		tag := strings.Trim(raw[2:len(raw)-2], " ")
+		if i := strings.Index(tag, "default.Get"); i == 0 {
+			s, found = dvf.getValue(tag[len("default.Get"):])
+		}
+
+		if !found {
+			return raw
+		}
+		return s
+	})
+}
+
+func (dvf DefaultValuesFilter) getValue(parameters string) (string, bool) {
+	regexPattern := `\(\s*(?:'|")?(?P<expression>.+?)(?:'|")?\s*\)`
+
+	expression, found := dvf.RegexHelper.GetStringPart(parameters, regexPattern, "expression")
+	if !found {
+		return "", false
+	}
+
+	values := strings.Split(expression, ",")
+
+	if len(values) != 2 {
+		return "", false
+	}
+
+	if values[0] != "" {
+		return strings.TrimSpace(values[0]), true
+	}
+
+	return strings.TrimSpace(values[1]), true
+}

vars/filler_factory.go

@@ -13,6 +13,7 @@ type FillerFactory interface {
 	CreateStorageFiller(Engines *persist.PersistEngineBag) Filler
 	CreatePersistFiller(Engines *persist.PersistEngineBag) Filler
 	CreateDynamicVarsFiller(Engines *persist.PersistEngineBag) Filler
+	CreateDefaultValuesFilter(Engines *persist.PersistEngineBag) Filler
 }
 
 type MockFillerFactory struct{}
@@ -36,3 +37,7 @@ func (mff MockFillerFactory) CreatePersistFiller(engines *persist.PersistEngineB
 func (mff MockFillerFactory) CreateDynamicVarsFiller(engines *persist.PersistEngineBag) Filler {
 	return DynamicVarsFiller{Engines: engines, RegexHelper: utils.RegexHelper{}}
 }
+
+func (mff MockFillerFactory) CreateDefaultValuesFilter(engines *persist.PersistEngineBag) Filler {
+	return DefaultValuesFilter{Engines: engines, RegexHelper: utils.RegexHelper{}}
+}

vars/vars_processor.go

@@ -18,6 +18,7 @@ func (fp VarsProcessor) Eval(req *definition.Request, m *definition.Mock) {
 	storageFiller := fp.FillerFactory.CreateStorageFiller(fp.PersistEngines)
 	persistFiller := fp.FillerFactory.CreatePersistFiller(fp.PersistEngines)
 	dynamicVarsFiller := fp.FillerFactory.CreateDynamicVarsFiller(fp.PersistEngines)
+	defaultValuesVarsFiller := fp.FillerFactory.CreateDefaultValuesFilter(fp.PersistEngines)
 	entityActions := persist.EntityActions{fp.PersistEngines}
 
 	fp.walkAndFill(requestFiller, m, true)
@@ -29,6 +30,7 @@ func (fp VarsProcessor) Eval(req *definition.Request, m *definition.Mock) {
 
 	// handle possible dynamic values and use it in storage again
 	fp.walkAndFill(dynamicVarsFiller, m, true)
+	fp.walkAndFill(defaultValuesVarsFiller, m, true)
 	fp.walkAndFill(storageFiller, m, true)
 
 	entityActions.ApplyActions(m)