代码语言：javascript复制
/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
/*
* the single part format:
*
* "HTTP/1.0 206 Partial Content" CRLF
* ... header ...
* "Content-Type: image/jpeg" CRLF
* "Content-Length: SIZE" CRLF
* "Content-Range: bytes START-END/SIZE" CRLF
* CRLF
* ... data ...
*
*
* the mutlipart format:
*
* "HTTP/1.0 206 Partial Content" CRLF
* ... header ...
* "Content-Type: multipart/byteranges; boundary=0123456789" CRLF
* CRLF
* CRLF
* "--0123456789" CRLF
* "Content-Type: image/jpeg" CRLF
* "Content-Range: bytes START0-END0/SIZE" CRLF
* CRLF
* ... data ...
* CRLF
* "--0123456789" CRLF
* "Content-Type: image/jpeg" CRLF
* "Content-Range: bytes START1-END1/SIZE" CRLF
* CRLF
* ... data ...
* CRLF
* "--0123456789--" CRLF
*/
typedef struct {
ngx_str_t boundary_header;
} ngx_http_range_filter_ctx_t;
static ngx_int_t ngx_http_range_header_filter_init(ngx_cycle_t *cycle);
static ngx_int_t ngx_http_range_body_filter_init(ngx_cycle_t *cycle);
...
static ngx_http_output_header_filter_pt ngx_http_next_header_filter;
static ngx_http_output_body_filter_pt ngx_http_next_body_filter;
static ngx_int_t ngx_http_range_header_filter(ngx_http_request_t *r)
{
ngx_int_t rc;
ngx_uint_t boundary, suffix, i;
u_char *p;
size_t len;
off_t start, end;
ngx_http_range_t *range;
ngx_http_range_filter_ctx_t *ctx;
if (r->http_version < NGX_HTTP_VERSION_10
|| r->headers_out.status != NGX_HTTP_OK
|| r->headers_out.content_length_n == -1
|| !r->filter_allow_ranges)
{
return ngx_http_next_header_filter(r);
}
if (r->headers_in.range == NULL
|| r->headers_in.range->value.len < 7
|| ngx_strncasecmp(r->headers_in.range->value.data, "bytes=", 6) != 0)
{
r->headers_out.accept_ranges = ngx_list_push(&r->headers_out.headers);
if (r->headers_out.accept_ranges == NULL) {
return NGX_ERROR;
}
r->headers_out.accept_ranges->key.len = sizeof("Accept-Ranges") - 1;
r->headers_out.accept_ranges->key.data = (u_char *) "Accept-Ranges";
r->headers_out.accept_ranges->value.len = sizeof("bytes") - 1;
r->headers_out.accept_ranges->value.data = (u_char *) "bytes";
return ngx_http_next_header_filter(r);
}
// 申请5个range
ngx_init_array(r->headers_out.ranges, r->pool, 5, sizeof(ngx_http_range_t),
NGX_ERROR);
rc = 0;
range = NULL;
// 拿到客户端请求的range范围
p = r->headers_in.range->value.data 6;
// 每一个循环解析一个range
for ( ;; ) {
start = 0;
end = 0;
suffix = 0;
// 容错，跳过空格
while (*p == ' ') { p ; }
/*
格式：
a-b
-b
a-
a-b,c-
-a
不写开头则说明是从倒数abs(-a)字节开始，不写结尾则说明是到最后一个字节，
内容可能是多个以上的组合
*/
// 第一个有效字符不是-，则说明是属于a-[b]格式,b可能没有
if (*p != '-') {
// 不是数字则报错
if (*p < '0' || *p > '9') {
rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
break;
}
// 整数化a，直到遇到第一个非数字
while (*p >= '0' && *p <= '9') {
start = start * 10 *p - '0';
}
// 容错，过滤空格
while (*p == ' ') { p ; }
// 第一个数字后面不是-则报错
if (*p != '-') {
rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
break;
}
// 请求的范围大于返回内容的大小范围，则报错
if (start >= r->headers_out.content_length_n) {
rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
break;
}
// 容错，过滤-后面的空格
while (*p == ' ') { p ; }
// 如果a-后面是逗号或者 则说明是最后一个range
if (*p == ',' || *p == ' ') {
ngx_test_null(range, ngx_push_array(&r->headers_out.ranges),
NGX_ERROR);
// 记录该range的范围，从start到最后一个字节
range->start = start;
range->end = r->headers_out.content_length_n;
// 如果当前字符是 则直接break退出循环，解析结束
if (*p != ',') {
break;
}
// 否则继续解析下一个range
continue;
}
} else {
// range的第一个字节是-说明是-a格式，不是代表从第一个字节开始，而是到倒数第几个算起
suffix = 1;
p ;
}
// 走到这说明是需要解析end的，即不是a-(,| )这种格式,但是可能是a-b或者-b格式
if (*p < '0' || *p > '9') {
rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
break;
}
// 不管是哪种格式，首先计算end
while (*p >= '0' && *p <= '9') {
end = end * 10 *p - '0';
}
while (*p == ' ') { p ; }
// end的后面不是或 则格式错误
if (*p != ',' && *p != ' ') {
rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
break;
}
/*
计算完end再计算start，没有写range的开始字节，
则说明start是倒数第几个字节，end这时候代表是一直到最后，而不是结束字节的位置
*/
if (suffix) {
start = r->headers_out.content_length_n - end;
// 为了统一处理-b和a-b两种格式，下面统一进行了end 1处理，所以这里需要先减一
end = r->headers_out.content_length_n - 1;
}
// 范围不合法
if (start > end) {
rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
break;
}
// 记录到一个range结构体中
ngx_test_null(range, ngx_push_array(&r->headers_out.ranges), NGX_ERROR);
range->start = start;
// 取最小值
if (end >= r->headers_out.content_length_n) {
/*
* Download Accelerator sends the last byte position
* that equals to the file length
*/
range->end = r->headers_out.content_length_n;
} else {
range->end = end 1;
}
// 不等于逗号说明等于 ，解析结束
if (*p != ',') {
break;
}
}
// 解析出错
if (rc) {
/* rc == NGX_HTTP_RANGE_NOT_SATISFIABLE */
// 状态是416，说明请求的范围不合法，返回合法的范围给客户端
r->headers_out.status = rc;
r->headers_out.ranges.nelts = 0;
r->headers_out.content_range = ngx_list_push(&r->headers_out.headers);
if (r->headers_out.content_range == NULL) {
return NGX_ERROR;
}
r->headers_out.content_range->key.len = sizeof("Content-Range") - 1;
r->headers_out.content_range->key.data = (u_char *) "Content-Range";
r->headers_out.content_range->value.data =
ngx_palloc(r->pool, 8 20 1);
if (r->headers_out.content_range->value.data == NULL) {
return NGX_ERROR;
}
r->headers_out.content_range->value.len =
ngx_snprintf((char *) r->headers_out.content_range->value.data,
8 20 1, "bytes */" OFF_T_FMT,
r->headers_out.content_length_n);
// 不返回数据，清空content-length
r->headers_out.content_length_n = -1;
if (r->headers_out.content_length) {
r->headers_out.content_length->key.len = 0;
r->headers_out.content_length = NULL;
}
return rc;
} else {
// 206
r->headers_out.status = NGX_HTTP_PARTIAL_CONTENT;
// 只有一个range，设置range相关的响应头
if (r->headers_out.ranges.nelts == 1) {
r->headers_out.content_range =
ngx_list_push(&r->headers_out.headers);
if (r->headers_out.content_range == NULL) {
return NGX_ERROR;
}
r->headers_out.content_range->key.len = sizeof("Content-Range") - 1;
r->headers_out.content_range->key.data = (u_char *) "Content-Range";
ngx_test_null(r->headers_out.content_range->value.data,
ngx_palloc(r->pool, 6 20 1 20 1 20 1),
NGX_ERROR);
/* "Content-Range: bytes SSSS-EEEE/TTTT" header */
r->headers_out.content_range->value.len =
ngx_snprintf((char *)
r->headers_out.content_range->value.data,
6 20 1 20 1 20 1,
"bytes " OFF_T_FMT "-" OFF_T_FMT "/" OFF_T_FMT,
range->start, range->end - 1,
r->headers_out.content_length_n);
r->headers_out.content_length_n = range->end - range->start;
} else {
#if 0
/* TODO: what if no content_type ?? */
if (!(r->headers_out.content_type =
ngx_http_add_header(&r->headers_out, ngx_http_headers_out)))
{
return NGX_ERROR;
}
#endif
// 多个range返回的格式不一样
ngx_http_create_ctx(r, ctx, ngx_http_range_body_filter_module,
sizeof(ngx_http_range_filter_ctx_t), NGX_ERROR);
len = 4 10 2 14 r->headers_out.content_type->value.len
2 21 1;
if (r->headers_out.charset.len) {
len = 10 r->headers_out.charset.len;
}
ngx_test_null(ctx->boundary_header.data, ngx_palloc(r->pool, len),
NGX_ERROR);
// 获取一个分隔多个range内容的字符串
boundary = ngx_next_temp_number(0);
/*
* The boundary header of the range:
* CRLF
* "--0123456789" CRLF
* "Content-Type: image/jpeg" CRLF
* "Content-Range: bytes "
*/
// 设置响应头
if (r->headers_out.charset.len) {
ctx->boundary_header.len =
ngx_snprintf((char *) ctx->boundary_header.data, len,
CRLF "--0" NGX_UINT_T_FMT CRLF
"Content-Type: %s; charset=%s" CRLF
"Content-Range: bytes ",
boundary,
r->headers_out.content_type->value.data,
r->headers_out.charset.data);
r->headers_out.charset.len = 0;
} else {
ctx->boundary_header.len =
ngx_snprintf((char *) ctx->boundary_header.data, len,
CRLF "--0" NGX_UINT_T_FMT CRLF
"Content-Type: %s" CRLF
"Content-Range: bytes ",
boundary,
r->headers_out.content_type->value.data);
}
// 更新content-type为multipart/byteranges; boundary="xxx"
ngx_test_null(r->headers_out.content_type->value.data,
ngx_palloc(r->pool, 31 10 1),
NGX_ERROR);
/* "Content-Type: multipart/byteranges; boundary=0123456789" */
r->headers_out.content_type->value.len =
ngx_snprintf((char *)
r->headers_out.content_type->value.data,
31 10 1,
"multipart/byteranges; boundary=0"
NGX_UINT_T_FMT,
boundary);
/* the size of the last boundary CRLF "--0123456789--" CRLF */
len = 4 10 4;
/*
设置响应头
xxxx
Content-Type: image/png
Content-Range: bytes a-b/content-length
内容
xxxx
Content-Type: image/png
Content-Range: bytes c-d/content-length
内容
xxxx
// 这里貌似没有设置每个range里的content-type
*/
range = r->headers_out.ranges.elts;
for (i = 0; i < r->headers_out.ranges.nelts; i ) {
// content_range记录了一个range的信息， Content-Range: bytes a-b/content-length
ngx_test_null(range[i].content_range.data,
ngx_palloc(r->pool, 20 1 20 1 20 5),
NGX_ERROR);
/* the size of the range: "SSSS-EEEE/TTTT" CRLF CRLF */
// 这里的content_length_n是有效数据的长度
range[i].content_range.len =
ngx_snprintf((char *) range[i].content_range.data,
20 1 20 1 20 5,
OFF_T_FMT "-" OFF_T_FMT "/" OFF_T_FMT CRLF CRLF,
range[i].start, range[i].end - 1,
r->headers_out.content_length_n);
// 这里len是最后返回的数据的长度
len = ctx->boundary_header.len range[i].content_range.len
(size_t) (range[i].end - range[i].start);
}
r->headers_out.content_length_n = len;
r->headers_out.content_length = NULL;
}
}
return ngx_http_next_header_filter(r);
}
static ngx_int_t ngx_http_range_body_filter(ngx_http_request_t *r,
ngx_chain_t *in)
{
ngx_uint_t i;
ngx_buf_t *b;
ngx_chain_t *out, *hcl, *rcl, *dcl, **ll;
ngx_http_range_t *range;
ngx_http_range_filter_ctx_t *ctx;
// 没有则跳过，在header filter里设置
if (r->headers_out.ranges.nelts == 0) {
return ngx_http_next_body_filter(r, in);
}
/*
* the optimized version for the static files only
* that are passed in the single file buf
*/
if (in && in->buf->in_file && in->buf->last_buf) {
range = r->headers_out.ranges.elts;
if (r->headers_out.ranges.nelts == 1) {
in->buf->file_pos = range->start;
in->buf->file_last = range->end;
return ngx_http_next_body_filter(r, in);
}
// 获取boundary内容
ctx = ngx_http_get_module_ctx(r, ngx_http_range_body_filter_module);
ll = &out;
for (i = 0; i < r->headers_out.ranges.nelts; i ) {
/*
* The boundary header of the range:
* CRLF
* "--0123456789" CRLF
* "Content-Type: image/jpeg" CRLF
* "Content-Range: bytes "
*/
ngx_test_null(b, ngx_calloc_buf(r->pool), NGX_ERROR);
b->memory = 1;
b->pos = ctx->boundary_header.data;
b->last = ctx->boundary_header.data ctx->boundary_header.len;
ngx_test_null(hcl, ngx_alloc_chain_link(r->pool), NGX_ERROR);
hcl->buf = b;
/* "SSSS-EEEE/TTTT" CRLF CRLF */
ngx_test_null(b, ngx_calloc_buf(r->pool), NGX_ERROR);
b->temporary = 1;
b->pos = range[i].content_range.data;
b->last = range[i].content_range.data range[i].content_range.len;
ngx_test_null(rcl, ngx_alloc_chain_link(r->pool), NGX_ERROR);
rcl->buf = b;
/* the range data */
ngx_test_null(b, ngx_calloc_buf(r->pool), NGX_ERROR);
b->in_file = 1;
b->file_pos = range[i].start;
b->file_last = range[i].end;
b->file = in->buf->file;
ngx_alloc_link_and_set_buf(dcl, b, r->pool, NGX_ERROR);
*ll = hcl;
hcl->next = rcl;
rcl->next = dcl;
ll = &dcl->next;
}
/* the last boundary CRLF "--0123456789--" CRLF */
ngx_test_null(b, ngx_calloc_buf(r->pool), NGX_ERROR);
b->temporary = 1;
b->last_buf = 1;
ngx_test_null(b->pos, ngx_palloc(r->pool, 4 10 4), NGX_ERROR);
b->last = ngx_cpymem(b->pos, ctx->boundary_header.data, 4 10);
*b->last = '-'; *b->last = '-';
*b->last = CR; *b->last = LF;
ngx_alloc_link_and_set_buf(hcl, b, r->pool, NGX_ERROR);
*ll = hcl;
return ngx_http_next_body_filter(r, out);
}
/* TODO: alert */
return ngx_http_next_body_filter(r, in);
}
// 挂载到header和body的filter链表上
static ngx_int_t ngx_http_range_header_filter_init(ngx_cycle_t *cycle)
{
ngx_http_next_header_filter = ngx_http_top_header_filter;
ngx_http_top_header_filter = ngx_http_range_header_filter;
return NGX_OK;
}
static ngx_int_t ngx_http_range_body_filter_init(ngx_cycle_t *cycle)
{
ngx_http_next_body_filter = ngx_http_top_body_filter;
ngx_http_top_body_filter = ngx_http_range_body_filter;
return NGX_OK;
}
