github.com/koko1123/flow-go-1@v0.29.6/engine/access/rest/middleware/common_query_params.go (about)

     1  package middleware
     2  
     3  import (
     4  	"net/http"
     5  	"strings"
     6  
     7  	"github.com/gorilla/mux"
     8  )
     9  
    10  const ExpandQueryParam = "expand"
    11  const selectQueryParam = "select"
    12  
    13  // commonQueryParamMiddleware generates a Middleware function that extracts the given query parameter from the request
    14  // and adds it to the request context as a key value pair with the key as the query param name.
    15  // e.g. for queryParamName "fields", if the request url contains <some url>?fields=field1,field2,..fieldN,
    16  // the middleware returned by commonQueryParamMiddleware will add the key - "fields" to the request context with value
    17  // as a map containing each of the field as key and value true ["field"]->true, ["fields2"] -> true etc when it is executed
    18  func commonQueryParamMiddleware(queryParamName string) mux.MiddlewareFunc {
    19  	return func(handler http.Handler) http.Handler {
    20  		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
    21  			if value, ok := req.URL.Query()[queryParamName]; ok {
    22  				if len(value) > 0 && len(value[0]) > 0 {
    23  					values := strings.Split(value[0], ",")
    24  					// save the query param value in the request context
    25  					req = addRequestAttribute(req, queryParamName, values)
    26  				}
    27  			}
    28  			handler.ServeHTTP(w, req)
    29  		})
    30  	}
    31  }
    32  
    33  // QueryExpandable middleware extracts out the 'expand' query param field if present in the request
    34  func QueryExpandable() mux.MiddlewareFunc {
    35  	return commonQueryParamMiddleware(ExpandQueryParam)
    36  }
    37  
    38  // QuerySelect middleware extracts out the 'select' query param field if present in the request
    39  func QuerySelect() mux.MiddlewareFunc {
    40  	return commonQueryParamMiddleware(selectQueryParam)
    41  }
    42  
    43  func getField(req *http.Request, key string) ([]string, bool) {
    44  	value, found := getRequestAttribute(req, key)
    45  	if !found {
    46  		return nil, false
    47  	}
    48  	valueAsStringSlice, ok := value.([]string)
    49  	return valueAsStringSlice, ok
    50  }
    51  
    52  func GetFieldsToExpand(req *http.Request) ([]string, bool) {
    53  	return getField(req, ExpandQueryParam)
    54  }
    55  
    56  func GetFieldsToSelect(req *http.Request) ([]string, bool) {
    57  	return getField(req, selectQueryParam)
    58  }