feat: added low level API for Database exports

Signed-off-by: SoXX <soxx@fenpa.ws>

go.mod

@@ -7,3 +7,5 @@ require (
 	github.com/joho/godotenv v1.5.1
 	golang.org/x/time v0.3.0
 )
+
+require golang.org/x/net v0.18.0 // indirect

go.sum

@@ -6,5 +6,7 @@ github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/maxatome/go-testdeep v1.12.0 h1:Ql7Go8Tg0C1D/uMMX59LAoYK7LffeJQ6X2T04nTH68g=
 github.com/maxatome/go-testdeep v1.12.0/go.mod h1:lPZc/HAcJMP92l7yI6TRz1aZN5URwUBUAfUNvrclaNM=
+golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
+golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
 golang.org/x/time v0.3.0 h1:rg5rLMjNzMS1RkNLzCG38eapWhnYLFYXDXj2gOlr8j4=
 golang.org/x/time v0.3.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=

pkg/e621/endpoints/dbexport.go

@@ -0,0 +1,117 @@
+package endpoints
+
+import (
+	"fmt"
+	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/model"
+	"git.dragse.it/anthrove/e621-sdk-go/pkg/e621/utils"
+	"golang.org/x/net/html"
+	"net/http"
+	"strings"
+)
+
+// GetDBExportList retrieves a list of files available in the e621 database export.
+//
+// This function performs an HTTP GET request to the e621 database export endpoint and parses
+// the HTML content to extract the links to export files with the ".csv.gz" extension.
+//
+// Parameters:
+//   - requestContext: The context for the API request, including the host, user agent, username, and API key.
+//
+// Returns:
+//   - []string: A slice of file names with the ".csv.gz" extension.
+//   - error: An error, if any, encountered during the API request, response handling, or HTML parsing.
+func GetDBExportList(requestContext model.RequestContext) ([]string, error) {
+	// Create a new HTTP GET request.
+	r, err := http.NewRequest("GET", fmt.Sprintf("https://e621.net/db_export/"), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	r.Header.Set("User-Agent", requestContext.UserAgent)
+	r.Header.Add("Accept", "application/json")
+	r.SetBasicAuth(requestContext.Username, requestContext.APIKey)
+
+	// Send the request using the provided http.Client.
+	resp, err := requestContext.Client.Do(r)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check if the HTTP response status code indicates success (2xx range).
+	if resp.StatusCode < 200 || resp.StatusCode > 300 {
+		// If the status code is outside the 2xx range, return an error based on the status code.
+		return nil, utils.StatusCodesToError(resp.StatusCode)
+	}
+
+	// Parse the HTML content
+	tokenizer := html.NewTokenizer(resp.Body)
+	var files []string
+
+	// Iterate through the HTML tokens
+	for {
+		tokenType := tokenizer.Next()
+
+		switch tokenType {
+		case html.ErrorToken:
+			// End of the HTML document
+			return files, nil
+		case html.StartTagToken, html.SelfClosingTagToken:
+			token := tokenizer.Token()
+			if token.Data == "a" {
+				// Check if the anchor tag has an href attribute
+				for _, attr := range token.Attr {
+					if attr.Key == "href" {
+						// Filter out the parent directory link and only add links with ".csv.gz" extension
+						if !strings.HasPrefix(attr.Val, "../") && strings.HasSuffix(attr.Val, ".csv.gz") {
+							files = append(files, attr.Val)
+						}
+						break
+					}
+				}
+			}
+		}
+	}
+}
+
+// GetDBExportFile retrieves a specific file from the e621 database export.
+//
+// This function performs an HTTP GET request to the e621 database export endpoint to fetch a
+// particular file identified by its name.
+//
+// Parameters:
+//   - requestContext: The context for the API request, including the host, user agent, username, and API key.
+//   - file: The name of the file to be fetched from the database export.
+//
+// Returns:
+//   - *http.Response: The HTTP response containing the requested file (probably a csv.gz).
+//   - error: An error, if any, encountered during the API request or response handling.
+func GetDBExportFile(requestContext model.RequestContext, file string) (*http.Response, error) {
+	if file == "" {
+		return nil, fmt.Errorf("no file specified")
+	}
+
+	// Create a new HTTP GET request.
+	r, err := http.NewRequest("GET", fmt.Sprintf("https://e621.net/db_export/%s", file), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	r.Header.Set("User-Agent", requestContext.UserAgent)
+	r.Header.Add("Accept", "application/json")
+	r.SetBasicAuth(requestContext.Username, requestContext.APIKey)
+
+	// Send the request using the provided http.Client.
+	resp, err := requestContext.Client.Do(r)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check if the HTTP response status code indicates success (2xx range).
+	if resp.StatusCode < 200 || resp.StatusCode > 300 {
+		// If the status code is outside the 2xx range, return an error based on the status code.
+		return nil, utils.StatusCodesToError(resp.StatusCode)
+	}
+
+	return resp, nil
+
+}