#291 refresh cache if coin struct hash changed

cointop/config.go

@@ -47,11 +47,14 @@ type ConfigFileConfig struct {
 	API               interface{}            `toml:"api"`
 	Colorscheme       interface{}            `toml:"colorscheme"`
 	RefreshRate       interface{}            `toml:"refresh_rate"`
+	CoinStructHash    interface{}            `toml:"coin_struct_version"`
 	CacheDir          interface{}            `toml:"cache_dir"`
-	CompactNotation   interface{}            `toml:"compact_notation"`
-	EnableMouse       interface{}            `toml:"enable_mouse"`
-	Table             map[string]interface{} `toml:"table"`
-	Chart             map[string]interface{} `toml:"chart"`
+
+	CompactNotation interface{} `toml:"compact_notation"`
+	EnableMouse     interface{} `toml:"enable_mouse"`
+
+	Table map[string]interface{} `toml:"table"`
+	Chart map[string]interface{} `toml:"chart"`
 }
 
 // SetupConfig loads config file
@@ -278,7 +281,7 @@ func (ct *Cointop) ConfigToToml() ([]byte, error) {
 		"height":    ct.State.chartHeight,
 	}
 
-	var inputs = &ConfigFileConfig{
+	inputs := &ConfigFileConfig{
 		API:               ct.apiChoice,
 		Colorscheme:       ct.colorschemeName,
 		CoinMarketCap:     cmcIfc,
@@ -293,6 +296,7 @@ func (ct *Cointop) ConfigToToml() ([]byte, error) {
 		CacheDir:          ct.State.cacheDir,
 		Table:             tableMapIfc,
 		Chart:             chartMapIfc,
+		CoinStructHash:    getStructHash(Coin{}),
 		CompactNotation:   ct.State.compactNotation,
 		EnableMouse:       ct.State.enableMouse,
 	}

cointop/list.go

@@ -29,9 +29,11 @@ func (ct *Cointop) UpdateCoins() error {
 		log.Debug("UpdateCoins() soft cache hit")
 	}
 
-	// cache miss
-	if allCoinsSlugMap == nil {
-		log.Debug("UpdateCoins() cache miss")
+	// cache miss or coin struct has been changed from the last time
+	isCacheMissed := allCoinsSlugMap == nil
+	isCoinStructHashChanged := getStructHash(Coin{}) != ct.config.CoinStructHash
+	if isCacheMissed || isCoinStructHashChanged {
+		log.Debug("UpdateCoins() cache miss or coin struct has changed")
 		ch := make(chan []types.Coin)
 		err = ct.api.GetAllCoinData(ct.State.currencyConversion, ch)
 		if err != nil {

cointop/util.go

@@ -2,8 +2,10 @@ package cointop
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"encoding/gob"
 	"fmt"
+	"reflect"
 	"regexp"
 	"strings"
 	"sync"
@@ -66,3 +68,34 @@ func normalizeFloatString(input string, allowNegative bool) string {
 
 	return ""
 }
+
+func getStructHash(x interface{}) string {
+	raw := make(map[string]string)
+	collectTypeFields(reflect.TypeOf(x), raw)
+
+	h := sha256.New()
+	h.Write([]byte(fmt.Sprintf("%v", raw)))
+
+	return fmt.Sprintf("%x", h.Sum(nil))
+}
+
+func collectTypeFields(t reflect.Type, m map[string]string) {
+	// Return if not struct or pointer to struct.
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	if t.Kind() != reflect.Struct {
+		return
+	}
+
+	// Iterate through fields collecting names in map.
+	for i := 0; i < t.NumField(); i++ {
+		sf := t.Field(i)
+		m[sf.Name] = fmt.Sprintf("%v", sf)
+
+		// Recurse into anonymous fields.
+		if t.Kind() == reflect.Struct {
+			collectTypeFields(sf.Type, m)
+		}
+	}
+}

cointop/util_test.go

@@ -0,0 +1,86 @@
+package cointop
+
+import "testing"
+
+func Test_getStructHash(t *testing.T) {
+	type SCoin struct {
+		Name       string
+		Properties struct {
+			P7D  int
+			P10D int
+		}
+	}
+	type SCoin1 struct {
+		Name       string
+		Properties struct {
+			P7D  int
+			P10D int
+		}
+	}
+	type SCoin2 struct {
+		Name       interface{}
+		Properties struct {
+			P7D  int
+			P10D int
+		}
+	}
+	type SCoin3 struct {
+		Name       string
+		Age        int
+		Properties *struct {
+			P7D  int
+			P10D int
+		}
+	}
+	type args struct {
+		str1 interface{}
+		str2 interface{}
+	}
+
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "the same structs",
+			args: args{
+				str1: SCoin{},
+				str2: SCoin{},
+			},
+			want: true,
+		},
+		{
+			name: "different structs but have similar fields",
+			args: args{
+				str1: SCoin{},
+				str2: SCoin1{},
+			},
+			want: true,
+		},
+		{
+			name: "different structs but have similar fields and different field type",
+			args: args{
+				str1: SCoin{},
+				str2: SCoin2{},
+			},
+			want: false,
+		},
+		{
+			name: "different structs and different fields",
+			args: args{
+				str1: SCoin{},
+				str2: SCoin3{},
+			},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cp := getStructHash(tt.args.str1) == getStructHash(tt.args.str2)
+			if cp != tt.want {
+				t.Errorf("getStructHash() = %v, want %v", cp, tt.want)
+			}
+		})
+	}
+}