assets.c File Reference

Content-hashed in-memory assets: registration, URL lookup and serving. More...

#include "assets_internal.h"
#include <cwist/sys/app/assets.h>
#include <cwist/core/crypto/sha256.h>
#include <cwist/core/mem/alloc.h>
#include <stdatomic.h>
#include <stdio.h>
#include <string.h>

Include dependency graph for assets.c:

Go to the source code of this file.

Macros
#define	ASSET_HASH_HEX   16

Typedefs
typedef struct cwist_asset_registry	cwist_asset_registry

Functions
cwist_error_t	cwist_app_asset_prefix (cwist_app *app, const char *url_prefix)
	Set the URL prefix under which assets are served.
cwist_error_t	cwist_app_asset_add (cwist_app *app, const char *name, const void *data, size_t len, const char *content_type)
	Publish an in-memory buffer as an asset.
cwist_error_t	cwist_app_asset_add_file (cwist_app *app, const char *name, const char *path, const char *content_type)
	Read a file from disk and publish it as an asset.
const char *	cwist_app_asset_url (cwist_app *app, const char *name)
	Return the URL of the newest asset registered under name.
bool	cwist_assets_match (cwist_app *app, const cwist_http_request *req, cwist_asset_match *out)
	Match an HTTP request to a registered asset.
void	cwist_assets_respond (cwist_http_request *req, cwist_http_response *res, const cwist_asset_match *match)
	Fill a response for a matched asset.
int	cwist_assets_clone (void **dst, const void *src)
	Deep-copy a registry (used when an app is cloned).
void	cwist_assets_destroy (void *registry)

Detailed Description

Content-hashed in-memory assets: registration, URL lookup and serving.

Assets are immutable once published. A registry is a newest-first singly linked list whose head is swapped in atomically, and nodes are only freed with the app, so a request that resolved an asset can keep using it while another thread registers more.

Definition in file assets.c.

Macro Definition Documentation

ASSET_HASH_HEX

#define ASSET_HASH_HEX   16

Definition at line 19 of file assets.c.

Typedef Documentation

cwist_asset_registry

typedef struct cwist_asset_registry cwist_asset_registry

Function Documentation

cwist_app_asset_add()

cwist_error_t cwist_app_asset_add	(	cwist_app *	app,
		const char *	name,
		const void *	data,
		size_t	len,
		const char *	content_type
	)

Publish an in-memory buffer as an asset.

Register an asset from memory. The data is copied.

Copies data; on success the asset is immutable and served under its content-hashed name. Duplicate content is a no-op.

Parameters

app	App instance; must not be NULL.
name	Logical asset name; must be a valid relative path.
data	Asset bytes; may be NULL only when len is 0.
len	Length of data in bytes.
content_type	Optional Content-Type override; if NULL a type is guessed from name.

Returns

Error result with code 0 on success, -1 on invalid arguments or allocation failure.

Definition at line 306 of file assets.c.

References cap, and cwist_alloc().

cwist_app_asset_add_file()

cwist_error_t cwist_app_asset_add_file	(	cwist_app *	app,
		const char *	name,
		const char *	path,
		const char *	content_type
	)

Read a file from disk and publish it as an asset.

Register an asset from a file, read once now.

The file is read fully into memory; on success its content is served like an asset added with cwist_app_asset_add().

Parameters

app	App instance; must not be NULL.
name	Logical asset name; must be a valid relative path.
path	Filesystem path to read; must not be NULL.
content_type	Optional Content-Type override; if NULL a type is guessed from name.

Returns

Error result with code 0 on success, -1 on invalid arguments, an unreadable file, or allocation failure.

Definition at line 336 of file assets.c.

References cap, cwist_alloc(), cwist_free(), and cwist_realloc().

cwist_app_asset_prefix()

cwist_error_t cwist_app_asset_prefix	(	cwist_app *	app,
		const char *	url_prefix
	)

Set the URL prefix under which assets are served.

Choose the URL prefix assets are served under.

Must be called before any asset is registered; fails once the registry is non-empty.

Parameters

app	App instance; must not be NULL.
url_prefix	Absolute path such as "/assets" (trailing '/' stripped), or "/" for the root.

Returns

Error result with code 0 on success, -1 on failure (NULL app, invalid prefix, or assets already registered).

Definition at line 197 of file assets.c.

References cap, and cwist_free().

cwist_app_asset_url()

const char * cwist_app_asset_url	(	cwist_app *	app,
		const char *	name
	)

Return the URL of the newest asset registered under name.

Content-hashed URL of the newest asset registered under name.

The returned string is owned by the asset registry and stays valid until the app is destroyed.

Parameters

app	App instance; must not be NULL.
name	Logical asset name.

Returns

Asset URL, or NULL if no such asset exists.

Definition at line 386 of file assets.c.

References cap.

cwist_assets_clone()

int cwist_assets_clone	(	void **	dst,
		const void *	src
	)

Deep-copy a registry (used when an app is cloned).

Copies the prefix and every asset, preserving newest-first order. On failure *dst stays NULL and no partial registry is left behind.

Parameters

dst	Receives the new registry; set to NULL first.
src	Registry to copy; may be NULL, which is treated as empty.

Returns

0 on success, -1 on allocation failure.

Definition at line 514 of file assets.c.

References ASSET_HASH_HEX, cap, cwist_alloc(), cwist_assets_destroy(), cwist_free(), cwist_strdup(), and head.

cwist_assets_destroy()

void cwist_assets_destroy

(

void *

registry

)

Free a registry and every asset in it. No-op for NULL.

Definition at line 570 of file assets.c.

References cap, and cwist_free().

Referenced by cwist_app_destroy(), and cwist_assets_clone().

cwist_assets_match()

bool cwist_assets_match	(	cwist_app *	app,
		const cwist_http_request *	req,
		cwist_asset_match *	out
	)

Match an HTTP request to a registered asset.

Only GET and HEAD requests under the registry prefix are considered. A request for a hashed (immutable) URL takes precedence over a logical name.

Parameters

app	App instance; must not be NULL.
req	Request to match; path must be present.
out	Filled with the matched asset and its immutability flag on match.

Returns

true on a match, false otherwise.

Definition at line 410 of file assets.c.

References cwist_asset_match::asset, cwist_app::assets, cap, CWIST_HTTP_GET, CWIST_HTTP_HEAD, cwist_sstring::data, cwist_asset_match::immutable, cwist_http_request::method, and cwist_http_request::path.

cwist_assets_respond()

void cwist_assets_respond	(	cwist_http_request *	req,
		cwist_http_response *	res,
		const cwist_asset_match *	match
	)

Fill a response for a matched asset.

Always sets ETag and Cache-Control; honors If-None-Match with 304 and an empty body. The body points directly at the asset data, which stays alive until the app is destroyed.

Parameters

req	Request being answered.
res	Response to fill.
match	Match from cwist_assets_match(); if NULL or without an asset, the response status is set to 500.

Definition at line 475 of file assets.c.

References cwist_http_response::body, cap, CWIST_ASSET_IMMUTABLE_CACHE, cwist_error_dispose(), cwist_http_header_get(), CWIST_HTTP_INTERNAL_ERROR, CWIST_HTTP_NOT_MODIFIED, CWIST_HTTP_OK, cwist_http_response_set_body_ptr(), cwist_sstring_assign(), cwist_http_request::headers, and cwist_http_response::status_code.