Initial QSfera import

Server/vendor/github.com/opencloud-eu/icap-client/client.go

@@ -0,0 +1,81 @@
+package icapclient
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"net/http"
+	"strings"
+)
+
+// Client represents the ICAP client who makes the ICAP server calls.
+type Client struct {
+	config Config // Store config for connection parameters
+}
+
+// NewClient creates a new ICAP client (no persistent connection).
+func NewClient(options ...ConfigOption) (Client, error) {
+	config := DefaultConfig()
+	for _, option := range options {
+		option(&config)
+	}
+	return Client{config: config}, nil
+}
+
+// Do make the ICAP request, creating and dropping a connection each time.
+func (c Client) Do(req Request) (res Response, err error) {
+	conn, err := NewICAPConn(c.config.ICAPConn)
+	if err != nil {
+		return Response{}, err
+	}
+
+	if err := conn.Connect(req.ctx, req.URL.Host); err != nil {
+		return Response{}, err
+	}
+	defer func() {
+		err = errors.Join(err, conn.Close())
+	}()
+
+	req.setDefaultRequestHeaders()
+
+	message, err := toICAPRequest(req)
+	if err != nil {
+		return Response{}, err
+	}
+
+	// send the ICAP message to the server
+	dataRes, err := conn.Send(message)
+	if err != nil {
+		return Response{}, err
+	}
+
+	res, err = toClientResponse(bufio.NewReader(strings.NewReader(string(dataRes))))
+	if err != nil {
+		return Response{}, err
+	}
+
+	// check if the message is fully done scanning or if it needs to be sent another chunk.
+	done := !(res.StatusCode == http.StatusContinue && !req.bodyFittedInPreview && req.previewSet)
+	if done {
+		return res, nil
+	}
+
+	// get the remaining body bytes.
+	data := req.remainingPreviewBytes
+	if !bodyIsChunked(string(data)) {
+		data = []byte(addHexBodyByteNotations(string(data)))
+	}
+
+	// hydrate the ICAP message with closing doubleCRLF suffix.
+	if !bytes.HasSuffix(data, []byte(doubleCRLF)) {
+		data = append(data, []byte(crlf)...)
+	}
+
+	// send the remaining body bytes to the server.
+	dataRes, err = conn.Send(data)
+	if err != nil {
+		return Response{}, err
+	}
+
+	return toClientResponse(bufio.NewReader(strings.NewReader(string(dataRes))))
+}