package fetch import ( "bytes" "context" "fmt" "net/http" "time" "github.com/goccy/go-json" ) const ( graphqlQuery = `{"query":"{block(number:%d){transactions{block{number,timestamp},hash,index,from{address},to{address},value,inputData,status,gasUsed}}}"}` ) type GraphqlOpts struct { GraphqlEndpoint string } type Graphql struct { graphqlEndpoint string httpClient *http.Client } func NewGraphqlFetcher(o GraphqlOpts) Fetch { return &Graphql{ httpClient: &http.Client{ Timeout: time.Second * 5, }, graphqlEndpoint: o.GraphqlEndpoint, } } func (f *Graphql) Block(ctx context.Context, blockNumber uint64) (FetchResponse, error) { var ( fetchResponse FetchResponse ) req, err := http.NewRequestWithContext(ctx, http.MethodPost, f.graphqlEndpoint, bytes.NewBufferString(fmt.Sprintf(graphqlQuery, blockNumber))) if err != nil { return FetchResponse{}, err } req.Header.Set("Content-Type", "application/json") resp, err := f.httpClient.Do(req) if err != nil { return FetchResponse{}, err } if resp.StatusCode >= http.StatusBadRequest { return FetchResponse{}, fmt.Errorf("error fetching block %s", resp.Status) } defer resp.Body.Close() if err := json.NewDecoder(resp.Body).Decode(&fetchResponse); err != nil { return FetchResponse{}, err } return fetchResponse, nil }