feat: get movies, url parametes parsing and validating, sql exeme querying

projects/greenlight/cmd/api/helpers.go

@@ -7,10 +7,12 @@ import (
 	"io"
 	"maps"
 	"net/http"
+	"net/url"
 	"strconv"
 	"strings"
 
 	"github.com/julienschmidt/httprouter"
+	"greenlight.debuggingjon.dev/internal/validator"
 )
 
 // Define an envelope type.
@@ -116,3 +118,60 @@ func (app *application) readJSON(w http.ResponseWriter, r *http.Request, dst any
 
 	return nil
 }
+
+// The readString() helper returns a string value from the query string, or the provided
+// default value if no matching key could be found.
+func (app *application) readString(qs url.Values, key string, defaultValue string) string {
+	// Extract the value for a given key from the query string. If no key exists this
+	// will return the empty string "".
+	s := qs.Get(key)
+
+	// If no key exists (or the value is empty) then return the default value.
+	if s == "" {
+		return defaultValue
+	}
+
+	// Otherwise return the string.
+	return s
+}
+
+// The readCSV() helper reads a string value from the query string and then splits it
+// into a slice on the comma character. If no matching key could be found, it returns
+// the provided default value.
+func (app *application) readCSV(qs url.Values, key string, defaultValue []string) []string {
+	// Extract the value from the query string.
+	csv := qs.Get(key)
+
+	// If no key exists (or the value is empty) then return the default value.
+	if csv == "" {
+		return defaultValue
+	}
+
+	// Otherwise parse the value into a []string slice and return it.
+	return strings.Split(csv, ",")
+}
+
+// The readInt() helper reads a string value from the query string and converts it to an
+// integer before returning. If no matching key could be found it returns the provided
+// default value. If the value couldn't be converted to an integer, then we record an
+// error message in the provided Validator instance.
+func (app *application) readInt(qs url.Values, key string, defaultValue int, v *validator.Validator) int {
+	// Extract the value from the query string.
+	s := qs.Get(key)
+
+	// If no key exists (or the value is empty) then return the default value.
+	if s == "" {
+		return defaultValue
+	}
+
+	// Try to convert the value to an int. If this fails, add an error message to the
+	// validator instance and return the default value.
+	i, err := strconv.Atoi(s)
+	if err != nil {
+		v.AddError(key, "must be an integer value")
+		return defaultValue
+	}
+
+	// Otherwise, return the converted integer value.
+	return i
+}

projects/greenlight/cmd/api/movies.go

@@ -209,3 +209,59 @@ func (app *application) deleteMovieHandler(w http.ResponseWriter, r *http.Reques
 		app.serverErrorResponse(w, r, err)
 	}
 }
+
+func (app *application) listMoviesHandler(w http.ResponseWriter, r *http.Request) {
+	// To keep things consistent with our other handlers, we'll define an input struct
+	// to hold the expected values from the request query string.
+	var input struct {
+		Title  string
+		Genres []string
+		data.Filters
+	}
+
+	// Initialize a new Validator instance.
+	v := validator.New()
+
+	// Call r.URL.Query() to get the url.Values map containing the query string data.
+	qs := r.URL.Query()
+
+	// Use our helpers to extract the title and genres query string values, falling back
+	// to defaults of an empty string and an empty slice respectively if they are not
+	// provided by the client.
+	input.Title = app.readString(qs, "title", "")
+	input.Genres = app.readCSV(qs, "genres", []string{})
+
+	// Get the page and page_size query string values as integers. Notice that we set
+	// the default page value to 1 and default page_size to 20, and that we pass the
+	// validator instance as the final argument here.
+	input.Page = app.readInt(qs, "page", 1, v)
+	input.PageSize = app.readInt(qs, "page_size", 20, v)
+
+	// Extract the sort query string value, falling back to "id" if it is not provided
+	// by the client (which will imply a ascending sort on movie ID).
+	input.Sort = app.readString(qs, "sort", "id")
+
+	// Add the supported sort values for this endpoint to the sort safelist.
+	input.SortSafelist = []string{"id", "title", "year", "runtime", "-id", "-title", "-year", "-runtime"}
+
+	// Execute the validation checks on the Filters struct and send a response
+	// containing the errors if necessary.
+	if data.ValidateFilters(v, input.Filters); !v.Valid() {
+		app.failedValidationResponse(w, r, v.Errors)
+		return
+	}
+
+	// Call the GetAll() method to retrieve the movies, passing in the various filter
+	// parameters.
+	movies, err := app.models.Movies.GetAll(input.Title, input.Genres, input.Filters)
+	if err != nil {
+		app.serverErrorResponse(w, r, err)
+		return
+	}
+
+	// Send a JSON response containing the movie data.
+	err = app.writeJSON(w, http.StatusOK, envelope{"movies": movies}, nil)
+	if err != nil {
+		app.serverErrorResponse(w, r, err)
+	}
+}

projects/greenlight/cmd/api/routes.go

@@ -17,7 +17,7 @@ func (app *application) routes() *httprouter.Router {
 	// Likewise, convert the methodNotAllowedResponse() helper to a http.Handler and set
 	// it as the custom error handler for 405 Method Not Allowed responses.
 	router.MethodNotAllowed = http.HandlerFunc(app.methodNotAllowedResponse)
-
+	router.HandlerFunc(http.MethodGet, "/v1/movies", app.listMoviesHandler)
 	router.HandlerFunc(http.MethodGet, "/v1/healthcheck", app.healthcheckHandler)
 	router.HandlerFunc(http.MethodPost, "/v1/movies", app.createMovieHandler)
 	router.HandlerFunc(http.MethodGet, "/v1/movies/:id", app.showMovieHandler)