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Former-commit-id: 3cfe87da405d0ff749e1a1010660c556b047f333

_future/param_parser.go

@@ -0,0 +1,163 @@
+package router
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+type ParamTmpl struct {
+	// id
+	Name string
+	// int range(1,5)!fail # fail fails on int parse or on range, it will work reclusive
+	Expression string
+	// fail
+	FailStatusCode int
+
+	Macro MacroTmpl
+}
+
+type MacroTmpl struct {
+	// int
+	Name string
+	// Macro will allow more than one funcs.
+	// []*MacroFuncs{ {Name: range, Params: []string{1,5}}}
+	Funcs []MacroFuncTmpl
+}
+
+type MacroFuncTmpl struct {
+	// range
+	Name string
+	// 1,5
+	Params []string
+}
+
+const (
+	ParamNameSeperator = ':'
+	FuncSeperator      = ' '
+	FuncStart          = '('
+	FuncEnd            = ')'
+	FuncParamSeperator = ','
+	FailSeparator      = '!'
+	ORSymbol           = '|'
+	ANDSymbol          = '&'
+)
+
+const DefaultFailStatusCode = 0
+
+// Parse i.e:
+// id:int range(1,5) otherFunc(3) !404
+//
+// id        = param name | can front-end end here but the parser should add :any
+// int       = marco | can end here
+//
+// range     = marco's funcs(range)
+// 1,5       = range's  func.params | can end here
+//           +
+// otherFunc = marco's funcs(otherFunc)
+// 3         = otherFunc's func.params  | can end here
+//
+// 404      = fail http custom error status code -> handler , will fail rescuslive
+func ParseParam(source string) (*ParamTmpl, error) {
+	// first, do a simple check if that's 'valid'
+	sepIndex := strings.IndexRune(source, ParamNameSeperator)
+
+	if sepIndex <= 0 {
+		// if not found or
+		// if starts with :
+		return nil, fmt.Errorf("invalid source '%s', separator should be after the parameter name", source)
+	}
+
+	t := new(ParamTmpl)
+	// id:int range(1,5)
+	// id:int min(1) max(5)
+	// id:int range(1,5)!404 or !404, space doesn't matters on fail error code.
+	cursor := 0
+	for i := 0; i < len(source); i++ {
+		if source[i] == ParamNameSeperator {
+			if i+1 >= len(source) {
+				return nil, fmt.Errorf("missing marco or raw expression after seperator, on source '%s'", source)
+			}
+
+			// id: , take the left, skip the : and continue
+			t.Name = source[0:i]
+			// set the expression, after the i, i.e:
+			// int range(1,5)
+			t.Expression = source[i+1:]
+			// set the macro's name to the full expression
+			// because we don't know if the user has put functions
+			// and we follow the < left 'pattern'
+			//  (I don't know if that's valid but that is what
+			//  I think to do and is working).
+			t.Macro = MacroTmpl{Name: t.Expression}
+
+			// cursor knows the last known(parsed) char position.
+			cursor = i + 1
+			continue
+		}
+		// int ...
+		if source[i] == FuncSeperator {
+			// take the left part: int if it's the first
+			// space after the param name
+			if t.Macro.Name == t.Expression {
+				t.Macro.Name = source[cursor:i]
+			} // else we have one or more functions, skip.
+
+			cursor = i + 1
+			continue
+		}
+
+		if source[i] == FuncStart {
+			// take the left part: range
+			funcName := source[cursor:i]
+			t.Macro.Funcs = append(t.Macro.Funcs, MacroFuncTmpl{Name: funcName})
+
+			cursor = i + 1
+			continue
+		}
+		// 1,5)
+		if source[i] == FuncEnd {
+			// check if we have end parenthesis but not start
+			if len(t.Macro.Funcs) == 0 {
+				return nil, fmt.Errorf("missing start macro's '%s' function, on source '%s'", t.Macro.Name, source)
+			}
+
+			// take the left part, between Start and End: 1,5
+			funcParamsStr := source[cursor:i]
+
+			funcParams := strings.SplitN(funcParamsStr, string(FuncParamSeperator), -1)
+			t.Macro.Funcs[len(t.Macro.Funcs)-1].Params = funcParams
+
+			cursor = i + 1
+			continue
+		}
+
+		if source[i] == FailSeparator {
+			// it should be the last element
+			// so no problem if we set the cursor here and work with that
+			// we will not need that later.
+			cursor = i + 1
+
+			if cursor >= len(source) {
+				return nil, fmt.Errorf("missing fail status code after '%q', on source '%s'", FailSeparator, source)
+			}
+
+			failCodeStr := source[cursor:] // should be the last
+			failCode, err := strconv.Atoi(failCodeStr)
+			if err != nil {
+				return nil, fmt.Errorf("fail status code should be integer but got '%s', on source '%s'", failCodeStr, source)
+			}
+
+			t.FailStatusCode = failCode
+
+			continue
+		}
+
+	}
+
+	if t.FailStatusCode == 0 {
+		t.FailStatusCode = DefaultFailStatusCode
+	}
+
+	return t, nil
+}