Fix concurrency issue.

I have no idea how this was missed, but ho hum.

README.md

@@ -9,6 +9,7 @@ Ps. It's Hasura friendly.
   - [Features](#features)
   - [Usage example](#usage-example)
     - [Environment variables](#environment-variables)
+    - [Modifiers on the fly](#modifiers-on-the-fly)
     - [Cache](#cache)
     - [Example reader code](#example-reader-code)
     - [Tips](#tips)
@@ -40,6 +41,11 @@ Therefore, I present you the simple client to which you can copy & paste your gr
 * `GRAPHQL_RETRIES_NUMBER` - Number of retries: Default: `1`
 * `GRAPHQL_RETRIES_DELAY` - Delay in retries in milliseconds. Default: `250`
 
+### Modifiers on the fly
+
+* `gql.SetEndpoint('your-endpoint-url')` - modifies endpoint, without the need to set the environment variable
+* `gql.SetOutput('byte')` - modifies output format, without the need to set the environment variable
+
 ### Cache
 
 You have two options to enable the cache:

query.go

@@ -70,52 +70,54 @@ func (c *BaseClient) NewQuery(q ...any) *Query {
 // It looks a bit weird because of the backward compatibility
 
 func (c *BaseClient) Query(queryContent string, queryVariables interface{}, queryHeaders map[string]interface{}) (any, error) {
-	query := c.NewQuery(queryContent, queryVariables)
-
 	var queryHash string
 	var cachedResponse []byte
-	var cacheBaseClient BaseClient
+
+	cbc := reflect.ValueOf(*c).Interface().(BaseClient)
+	cacheBaseClient := &cbc
+
+	query := cacheBaseClient.NewQuery(queryContent, queryVariables)
 
 	// Check for library specific headers
 	if len(queryHeaders) > 0 {
-		cacheBaseClient = reflect.ValueOf(*c).Interface().(BaseClient)
-		queryHeaders = c.parseQueryHeaders(queryHeaders)
-	}
+		queryHeadersModified := c.parseQueryHeaders(queryHeaders)
+		// compare if there are any changes
 
-	if c.cache.enabled {
-		queryHash = strutil.Md5(query.compiledQuery)
-		c.Logger.Debug(c, "Hash calculated;", "hash:", queryHash)
-
-		cachedResponse = c.cacheLookup(queryHash)
-		if cachedResponse != nil {
-			c.Logger.Debug(c, "Found cached response")
-			return c.decodeResponse(cachedResponse), nil
-		} else {
-			c.Logger.Debug(c, "No cached response found")
+		if !reflect.DeepEqual(queryHeadersModified, queryHeaders) {
+			cacheBaseClient.Logger.Debug(cacheBaseClient, "Headers modified, creating a new client")
 		}
 	}
 
-	response, err := c.executeQuery(query.compiledQuery, queryHeaders)
+	if cacheBaseClient.cache.enabled {
+		queryHash = strutil.Md5(fmt.Sprintf("%s-%+v", query.compiledQuery, queryHeaders))
+		cacheBaseClient.Logger.Debug(cacheBaseClient, "Hash calculated;", "hash:", queryHash)
+
+		cachedResponse = cacheBaseClient.cacheLookup(queryHash)
+		if cachedResponse != nil {
+			cacheBaseClient.Logger.Debug(cacheBaseClient, "Found cached response")
+			return cacheBaseClient.decodeResponse(cachedResponse), nil
+		} else {
+			cacheBaseClient.Logger.Debug(cacheBaseClient, "No cached response found")
+		}
+	}
+
+	response, err := cacheBaseClient.executeQuery(query.compiledQuery, queryHeaders)
 	if err != nil {
-		c.Logger.Error(c, "Error while executing query;", "error", err.Error())
+		cacheBaseClient.Logger.Error(cacheBaseClient, "Error while executing query;", "error", err.Error())
 		return nil, err
 	}
 
 	jsonData, err := json.Marshal(response)
 	if err != nil {
-		c.Logger.Error(c, "Error while converting to json;", "error", err.Error())
+		cacheBaseClient.Logger.Error(cacheBaseClient, "Error while converting to json;", "error", err.Error())
 		return nil, err
 	}
 
-	if c.cache.enabled {
-		c.cache.client.Set(queryHash, jsonData)
+	if cacheBaseClient.cache.enabled {
+		cacheBaseClient.cache.client.Set(queryHash, jsonData)
 	}
 
-	if len(queryHeaders) > 0 {
-		*c = cacheBaseClient
-	}
-
-	return c.decodeResponse(jsonData), err
+	return cacheBaseClient.decodeResponse(jsonData), err
 }
 
 func (c *BaseClient) decodeResponse(jsonData []byte) any {

query_test.go

@@ -339,3 +339,77 @@ func TestBaseClient_parseQueryHeaders(t *testing.T) {
 		})
 	}
 }
+
+func TestBaseClient_QueryCache(t *testing.T) {
+	type fields struct {
+		graphql_endpoint string
+		cache_enabled    bool
+	}
+	type args struct {
+		queryVariables interface{}
+		queryHeaders   map[string]interface{}
+		queryContent   string
+	}
+	tests := []struct {
+		want    any
+		args    args
+		name    string
+		fields  fields
+		wantErr bool
+	}{
+		{
+			name: "Test QueryCache - enabled",
+			fields: fields{
+				graphql_endpoint: "https://spacex-production.up.railway.app/",
+				cache_enabled:    true,
+			},
+			args: args{
+				queryContent: `query Dragons {
+					dragons {
+						name
+					}
+				}`,
+				queryHeaders: map[string]interface{}{
+					"x-apollo-operation-name": "Missions-Potato-Test-Golang",
+					"content-type":            "application/json",
+				},
+			},
+		},
+		{
+			name: "Test QueryCache - disabled",
+			fields: fields{
+				graphql_endpoint: "https://spacex-production.up.railway.app/",
+				cache_enabled:    false,
+			},
+			args: args{
+				queryContent: `query Dragons {
+					dragons {
+						name
+					}
+				}`,
+				queryHeaders: map[string]interface{}{
+					"x-apollo-operation-name": "Missions-Potato-Test-Golang",
+					"content-type":            "application/json",
+				},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			c := NewConnection()
+			c.cache.enabled = tt.fields.cache_enabled
+
+			if tt.fields.graphql_endpoint != "" {
+				c.endpoint = tt.fields.graphql_endpoint
+			}
+
+			_, err := c.Query(tt.args.queryContent, tt.args.queryVariables, tt.args.queryHeaders)
+			if !tt.wantErr {
+				assert.NoError(t, err)
+			} else {
+				assert.Error(t, err)
+			}
+		})
+	}
+}

request.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net/http"
+	"time"
 
 	"github.com/avast/retry-go/v4"
 )
@@ -50,6 +51,13 @@ func (c *BaseClient) executeQuery(query []byte, headers any) (result any, err er
 
 			return nil
 		},
+		retry.OnRetry(func(n uint, err error) {
+			c.Logger.Error(c, "Retrying query", "error", err.Error())
+		}),
+		retry.Attempts(uint(c.retries.max)),
+		retry.DelayType(retry.BackOffDelay),
+		retry.Delay(time.Duration(c.retries.delay)*time.Second),
+		retry.LastErrorOnly(true),
 	)
 
 	if len(queryResult.Errors) > 0 {