Files
probo/pkg/agent/tools/browser/fetch_robots.go
Émile Ré f5703d390b Enforce Go style rules across codebase
Apply five style rules: convert iota string enums to typed
string constants, replace errors.As with errors.AsType,
merge three-group imports into two groups, fix multiline
parameter/argument formatting, and replace fmt.Sprintf URL
construction with net/url.

Signed-off-by: Émile Ré <emile@probo.com>
2026-05-20 11:46:39 +04:00

123 lines
3.5 KiB
Go

// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
package browser
import (
"bufio"
"context"
"fmt"
"net/http"
"net/url"
"strings"
"time"
"go.probo.inc/probo/pkg/agent"
)
type (
robotsParams struct {
Domain string `json:"domain" jsonschema:"The domain to fetch robots.txt from (e.g. example.com)"`
}
robotsResult struct {
Found bool `json:"found"`
Sitemaps []string `json:"sitemaps,omitempty"`
Disallowed []string `json:"disallowed_paths,omitempty"`
ErrorDetail string `json:"error_detail,omitempty"`
}
)
func FetchRobotsTxtTool() agent.Tool {
client := &http.Client{Timeout: 10 * time.Second}
return agent.FunctionTool(
"fetch_robots_txt",
"Fetch and parse the robots.txt file for a domain. Returns sitemap URLs and disallowed paths, which can reveal hidden pages the crawler might miss.",
func(ctx context.Context, p robotsParams) (agent.ToolResult, error) {
if err := validatePublicDomain(p.Domain); err != nil {
return agent.ResultJSON(
robotsResult{
Found: false,
ErrorDetail: fmt.Sprintf("domain not allowed: %s", err),
},
), nil
}
u := &url.URL{
Scheme: "https",
Host: p.Domain,
Path: "/robots.txt",
}
req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
if err != nil {
return agent.ResultJSON(
robotsResult{
Found: false,
ErrorDetail: fmt.Sprintf("cannot create request: %s", err),
},
), nil
}
resp, err := client.Do(req)
if err != nil {
return agent.ResultJSON(
robotsResult{
Found: false,
ErrorDetail: fmt.Sprintf("cannot fetch robots.txt: %s", err),
},
), nil
}
defer func() { _ = resp.Body.Close() }()
if resp.StatusCode != http.StatusOK {
return agent.ResultJSON(
robotsResult{
Found: false,
ErrorDetail: fmt.Sprintf("robots.txt returned status %d", resp.StatusCode),
},
), nil
}
var result robotsResult
result.Found = true
scanner := bufio.NewScanner(resp.Body)
for scanner.Scan() {
line := strings.TrimSpace(scanner.Text())
// Directive names are case-insensitive but values
// (URLs, paths) are case-sensitive, so extract the
// original-case suffix from the raw line rather than
// reading it off the lowercased copy.
if after, ok := strings.CutPrefix(strings.ToLower(line), "sitemap:"); ok {
result.Sitemaps = append(result.Sitemaps, strings.TrimSpace(line[len(line)-len(after):]))
}
if after, ok := strings.CutPrefix(strings.ToLower(line), "disallow:"); ok {
path := strings.TrimSpace(line[len(line)-len(after):])
if path != "" && len(result.Disallowed) < 50 {
result.Disallowed = append(result.Disallowed, path)
}
}
}
return agent.ResultJSON(result), nil
},
)
}