1package tools
2
3import (
4 "context"
5 "encoding/json"
6 "fmt"
7 "io"
8 "net/http"
9 "strings"
10 "time"
11
12 md "github.com/JohannesKaufmann/html-to-markdown"
13 "github.com/PuerkitoBio/goquery"
14 "github.com/kujtimiihoxha/termai/internal/config"
15 "github.com/kujtimiihoxha/termai/internal/permission"
16)
17
18type FetchParams struct {
19 URL string `json:"url"`
20 Format string `json:"format"`
21 Timeout int `json:"timeout,omitempty"`
22}
23
24type FetchPermissionsParams struct {
25 URL string `json:"url"`
26 Format string `json:"format"`
27 Timeout int `json:"timeout,omitempty"`
28}
29
30type fetchTool struct {
31 client *http.Client
32 permissions permission.Service
33}
34
35const (
36 FetchToolName = "fetch"
37 fetchToolDescription = `Fetches content from a URL and returns it in the specified format.
38
39WHEN TO USE THIS TOOL:
40- Use when you need to download content from a URL
41- Helpful for retrieving documentation, API responses, or web content
42- Useful for getting external information to assist with tasks
43
44HOW TO USE:
45- Provide the URL to fetch content from
46- Specify the desired output format (text, markdown, or html)
47- Optionally set a timeout for the request
48
49FEATURES:
50- Supports three output formats: text, markdown, and html
51- Automatically handles HTTP redirects
52- Sets reasonable timeouts to prevent hanging
53- Validates input parameters before making requests
54
55LIMITATIONS:
56- Maximum response size is 5MB
57- Only supports HTTP and HTTPS protocols
58- Cannot handle authentication or cookies
59- Some websites may block automated requests
60
61TIPS:
62- Use text format for plain text content or simple API responses
63- Use markdown format for content that should be rendered with formatting
64- Use html format when you need the raw HTML structure
65- Set appropriate timeouts for potentially slow websites`
66)
67
68func NewFetchTool(permissions permission.Service) BaseTool {
69 return &fetchTool{
70 client: &http.Client{
71 Timeout: 30 * time.Second,
72 },
73 permissions: permissions,
74 }
75}
76
77func (t *fetchTool) Info() ToolInfo {
78 return ToolInfo{
79 Name: FetchToolName,
80 Description: fetchToolDescription,
81 Parameters: map[string]any{
82 "url": map[string]any{
83 "type": "string",
84 "description": "The URL to fetch content from",
85 },
86 "format": map[string]any{
87 "type": "string",
88 "description": "The format to return the content in (text, markdown, or html)",
89 },
90 "timeout": map[string]any{
91 "type": "number",
92 "description": "Optional timeout in seconds (max 120)",
93 },
94 },
95 Required: []string{"url", "format"},
96 }
97}
98
99func (t *fetchTool) Run(ctx context.Context, call ToolCall) (ToolResponse, error) {
100 var params FetchParams
101 if err := json.Unmarshal([]byte(call.Input), ¶ms); err != nil {
102 return NewTextErrorResponse("Failed to parse fetch parameters: " + err.Error()), nil
103 }
104
105 if params.URL == "" {
106 return NewTextErrorResponse("URL parameter is required"), nil
107 }
108
109 format := strings.ToLower(params.Format)
110 if format != "text" && format != "markdown" && format != "html" {
111 return NewTextErrorResponse("Format must be one of: text, markdown, html"), nil
112 }
113
114 if !strings.HasPrefix(params.URL, "http://") && !strings.HasPrefix(params.URL, "https://") {
115 return NewTextErrorResponse("URL must start with http:// or https://"), nil
116 }
117
118 p := t.permissions.Request(
119 permission.CreatePermissionRequest{
120 Path: config.WorkingDirectory(),
121 ToolName: FetchToolName,
122 Action: "fetch",
123 Description: fmt.Sprintf("Fetch content from URL: %s", params.URL),
124 Params: FetchPermissionsParams(params),
125 },
126 )
127
128 if !p {
129 return NewTextErrorResponse("Permission denied to fetch from URL: " + params.URL), nil
130 }
131
132 client := t.client
133 if params.Timeout > 0 {
134 maxTimeout := 120 // 2 minutes
135 if params.Timeout > maxTimeout {
136 params.Timeout = maxTimeout
137 }
138 client = &http.Client{
139 Timeout: time.Duration(params.Timeout) * time.Second,
140 }
141 }
142
143 req, err := http.NewRequestWithContext(ctx, "GET", params.URL, nil)
144 if err != nil {
145 return NewTextErrorResponse("Failed to create request: " + err.Error()), nil
146 }
147
148 req.Header.Set("User-Agent", "termai/1.0")
149
150 resp, err := client.Do(req)
151 if err != nil {
152 return NewTextErrorResponse("Failed to execute request: " + err.Error()), nil
153 }
154 defer resp.Body.Close()
155
156 if resp.StatusCode != http.StatusOK {
157 return NewTextErrorResponse(fmt.Sprintf("Request failed with status code: %d", resp.StatusCode)), nil
158 }
159
160 maxSize := int64(5 * 1024 * 1024) // 5MB
161 body, err := io.ReadAll(io.LimitReader(resp.Body, maxSize))
162 if err != nil {
163 return NewTextErrorResponse("Failed to read response body: " + err.Error()), nil
164 }
165
166 content := string(body)
167 contentType := resp.Header.Get("Content-Type")
168
169 switch format {
170 case "text":
171 if strings.Contains(contentType, "text/html") {
172 text, err := extractTextFromHTML(content)
173 if err != nil {
174 return NewTextErrorResponse("Failed to extract text from HTML: " + err.Error()), nil
175 }
176 return NewTextResponse(text), nil
177 }
178 return NewTextResponse(content), nil
179
180 case "markdown":
181 if strings.Contains(contentType, "text/html") {
182 markdown, err := convertHTMLToMarkdown(content)
183 if err != nil {
184 return NewTextErrorResponse("Failed to convert HTML to Markdown: " + err.Error()), nil
185 }
186 return NewTextResponse(markdown), nil
187 }
188
189 return NewTextResponse("```\n" + content + "\n```"), nil
190
191 case "html":
192 return NewTextResponse(content), nil
193
194 default:
195 return NewTextResponse(content), nil
196 }
197}
198
199func extractTextFromHTML(html string) (string, error) {
200 doc, err := goquery.NewDocumentFromReader(strings.NewReader(html))
201 if err != nil {
202 return "", err
203 }
204
205 text := doc.Text()
206 text = strings.Join(strings.Fields(text), " ")
207
208 return text, nil
209}
210
211func convertHTMLToMarkdown(html string) (string, error) {
212 converter := md.NewConverter("", true, nil)
213
214 markdown, err := converter.ConvertString(html)
215 if err != nil {
216 return "", err
217 }
218
219 return markdown, nil
220}