app: add code for macOS and Windows apps under 'app' (#12933)

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

app/tools/web_fetch.go

@@ -0,0 +1,128 @@
+//go:build windows || darwin
+
+package tools
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/ollama/ollama/auth"
+)
+
+type WebFetch struct{}
+
+type FetchRequest struct {
+	URL string `json:"url"`
+}
+
+type FetchResponse struct {
+	Title   string   `json:"title"`
+	Content string   `json:"content"`
+	Links   []string `json:"links"`
+}
+
+func (w *WebFetch) Name() string {
+	return "web_fetch"
+}
+
+func (w *WebFetch) Description() string {
+	return "Crawl and extract text content from web pages"
+}
+
+func (g *WebFetch) Schema() map[string]any {
+	schemaBytes := []byte(`{
+		"type": "object",
+		"properties": {
+			"url": {
+				"type": "string",
+				"description": "URL to crawl and extract content from"
+            }
+		},
+		"required": ["url"]
+	}`)
+	var schema map[string]any
+	if err := json.Unmarshal(schemaBytes, &schema); err != nil {
+		return nil
+	}
+	return schema
+}
+
+func (w *WebFetch) Prompt() string {
+	return ""
+}
+
+func (w *WebFetch) Execute(ctx context.Context, args map[string]any) (any, string, error) {
+	urlRaw, ok := args["url"]
+	if !ok {
+		return nil, "", fmt.Errorf("url parameter is required")
+	}
+	urlStr, ok := urlRaw.(string)
+	if !ok || strings.TrimSpace(urlStr) == "" {
+		return nil, "", fmt.Errorf("url must be a non-empty string")
+	}
+
+	result, err := performWebFetch(ctx, urlStr)
+	if err != nil {
+		return nil, "", err
+	}
+
+	return result, "", nil
+}
+
+func performWebFetch(ctx context.Context, targetURL string) (*FetchResponse, error) {
+	reqBody := FetchRequest{URL: targetURL}
+	jsonBody, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal request body: %w", err)
+	}
+
+	crawlURL, err := url.Parse("https://ollama.com/api/web_fetch")
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse fetch URL: %w", err)
+	}
+
+	query := crawlURL.Query()
+	query.Add("ts", strconv.FormatInt(time.Now().Unix(), 10))
+	crawlURL.RawQuery = query.Encode()
+
+	data := fmt.Appendf(nil, "%s,%s", http.MethodPost, crawlURL.RequestURI())
+	signature, err := auth.Sign(ctx, data)
+	if err != nil {
+		return nil, fmt.Errorf("failed to sign request: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, crawlURL.String(), bytes.NewBuffer(jsonBody))
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	if signature != "" {
+		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", signature))
+	}
+
+	client := &http.Client{Timeout: 30 * time.Second}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("failed to execute fetch request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("fetch API error (status %d)", resp.StatusCode)
+	}
+
+	var result FetchResponse
+	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		return nil, fmt.Errorf("failed to decode response: %w", err)
+	}
+
+	return &result, nil
+}