Documentation
¶
Overview ¶
Package utils provides shared, reusable algorithms. This file implements a generic BM25 search engine.
Usage:
type MyDoc struct { ID string; Body string }
corpus := []MyDoc{...}
engine := bm25.New(corpus, func(d MyDoc) string {
return d.ID + " " + d.Body
})
results := engine.Search("my query", 5)
Index ¶
- Constants
- func DerefStr(s *string, fallback string) string
- func DoRequestWithRetry(client *http.Client, req *http.Request) (*http.Response, error)
- func DownloadFile(urlStr, filename string, opts DownloadOptions) string
- func DownloadFileSimple(url, filename string) string
- func DownloadToFile(ctx context.Context, client *http.Client, req *http.Request, maxBytes int64) (string, error)
- func ExtractZipFile(zipPath string, targetDir string) error
- func IsAudioFile(filename, contentType string) bool
- func SanitizeFilename(filename string) string
- func SanitizeMessageContent(input string) string
- func SetDisableTruncation(enabled bool)
- func Truncate(s string, maxLen int) string
- func ValidateSkillIdentifier(identifier string) error
- type BM25Engine
- type BM25Option
- type BM25Result
- type DownloadOptions
Constants ¶
const ( // DefaultBM25K1 is the term-frequency saturation factor (typical range 1.2–2.0). // Higher values give more weight to repeated terms. DefaultBM25K1 = 1.2 // DefaultBM25B is the document-length normalization factor (0 = none, 1 = full). DefaultBM25B = 0.75 )
Variables ¶
This section is empty.
Functions ¶
func DerefStr ¶ added in v0.2.0
DerefStr dereferences a pointer to a string and returns the value or a fallback if the pointer is nil.
func DoRequestWithRetry ¶ added in v0.2.0
func DownloadFile ¶
func DownloadFile(urlStr, filename string, opts DownloadOptions) string
DownloadFile downloads a file from URL to a local temp directory. Returns the local file path or empty string on error.
func DownloadFileSimple ¶
DownloadFileSimple is a simplified version of DownloadFile without options
func DownloadToFile ¶ added in v0.2.0
func DownloadToFile(ctx context.Context, client *http.Client, req *http.Request, maxBytes int64) (string, error)
DownloadToFile streams an HTTP response body to a temporary file in small chunks (~32KB), keeping peak memory usage constant regardless of file size.
Parameters:
- ctx: context for cancellation/timeout
- client: HTTP client to use (caller controls timeouts, transport, etc.)
- req: fully prepared *http.Request (method, URL, headers, etc.)
- maxBytes: maximum bytes to download; 0 means no limit
Returns the path to the temporary file. The caller is responsible for removing it when done (defer os.Remove(path)).
On any error the temp file is cleaned up automatically.
func ExtractZipFile ¶ added in v0.2.0
ExtractZipFile extracts a ZIP archive from disk to targetDir. It reads entries one at a time from disk, keeping memory usage minimal.
Security: rejects path traversal attempts and symlinks.
func IsAudioFile ¶
IsAudioFile checks if a file is an audio file based on its filename extension and content type.
func SanitizeFilename ¶
SanitizeFilename removes potentially dangerous characters from a filename and returns a safe version for local filesystem storage.
func SanitizeMessageContent ¶ added in v0.2.0
SanitizeMessageContent removes Unicode control characters, format characters (RTL overrides, zero-width characters), and other non-graphic characters that could confuse an LLM or cause display issues in the agent UI.
func SetDisableTruncation ¶ added in v0.2.2
func SetDisableTruncation(enabled bool)
SetDisableTruncation globally enables or disables string truncation
func Truncate ¶
Truncate returns a truncated version of s with at most maxLen runes. Handles multi-byte Unicode characters properly. If the string is truncated, "..." is appended to indicate truncation.
func ValidateSkillIdentifier ¶ added in v0.2.0
ValidateSkillIdentifier validates that the given skill identifier (slug or registry name) is non-empty and does not contain path separators ("/", "\\") or ".." for security.
Types ¶
type BM25Engine ¶ added in v0.2.2
type BM25Engine[T any] struct { // contains filtered or unexported fields }
BM25Engine is a query-time BM25 search engine over a generic corpus. T is the document type; the caller supplies a TextFunc that extracts the searchable text from each document.
The engine is stateless between queries: no caching, no invalidation logic. All indexing work is performed inside Search() on every call, making it safe to use on corpora that change frequently.
func NewBM25Engine ¶ added in v0.2.2
func NewBM25Engine[T any](corpus []T, textFunc func(T) string, opts ...BM25Option) *BM25Engine[T]
NewBM25Engine creates a BM25Engine for the given corpus.
- corpus : slice of documents of any type T.
- textFunc : function that returns the searchable text for a document.
- opts : optional tuning (WithK1, WithB).
The corpus slice is referenced, not copied. Callers must not mutate it concurrently with Search().
func (*BM25Engine[T]) Search ¶ added in v0.2.2
func (e *BM25Engine[T]) Search(query string, topK int) []BM25Result[T]
Search ranks the corpus against query and returns the top-k results. Returns an empty slice (not nil) when there are no matches.
Complexity: O(N×L) for indexing + O(|Q|×avgPostingLen) for scoring, where N = corpus size, L = average document length, Q = query terms. Top-k extraction uses a fixed-size min-heap: O(candidates × log k).
type BM25Option ¶ added in v0.2.2
type BM25Option func(*bm25Config)
BM25Option is a functional option to configure a BM25Engine.
func WithB ¶ added in v0.2.2
func WithB(b float64) BM25Option
WithB overrides the document-length normalization factor (default 0.75).
func WithK1 ¶ added in v0.2.2
func WithK1(k1 float64) BM25Option
WithK1 overrides the term-frequency saturation constant (default 1.2).
type BM25Result ¶ added in v0.2.2
BM25Result is a single ranked result from a Search call.
Source Files