ngx_http_range_filter_module.c

Nginx ("engine x") 是一个高性能的 HTTP 和 反向代理 服务器

/*
 * 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 {
    off_t        start;
    off_t        end;
    ngx_str_t    content_range;
} ngx_http_range_t;


typedef struct {
    off_t        offset;
    ngx_str_t    boundary_header;
    ngx_array_t  ranges;
} ngx_http_range_filter_ctx_t;


static ngx_int_t ngx_http_range_header_filter_init(ngx_conf_t *cf);
static ngx_int_t ngx_http_range_body_filter_init(ngx_conf_t *cf);


static ngx_http_module_t  ngx_http_range_header_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_range_header_filter_init,     /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL,                                  /* merge location configuration */
};


ngx_module_t  ngx_http_range_header_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_range_header_filter_module_ctx, /* module context */
    NULL,                                  /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_http_module_t  ngx_http_range_body_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_range_body_filter_init,       /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL,                                  /* merge location configuration */
};


ngx_module_t  ngx_http_range_body_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_range_body_filter_module_ctx, /* module context */
    NULL,                                  /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


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)
{
    u_char                       *p;
    size_t                        len;
    off_t                         start, end;
    time_t                        if_range;
    ngx_int_t                     rc;
    ngx_uint_t                    suffix, i;
    ngx_atomic_uint_t             boundary;
    ngx_table_elt_t              *content_range;
    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 != r->main
        || r->headers_out.content_length_n == -1
        || !r->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,
                           (u_char *) "bytes=", 6)
           != 0)
    {
        goto next_filter;
    }

    if (r->headers_in.if_range && r->headers_out.last_modified_time != -1) {

        if_range = ngx_http_parse_time(r->headers_in.if_range->value.data,
                                       r->headers_in.if_range->value.len);

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http ir:%d lm:%d",
                       if_range, r->headers_out.last_modified_time);

        if (if_range != r->headers_out.last_modified_time) {
            goto next_filter;
        }
    }

    ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_range_filter_ctx_t));
    if (ctx == NULL) {
        return NGX_ERROR;
    }

    if (ngx_array_init(&ctx->ranges, r->pool, 1, sizeof(ngx_http_range_t))
        == NGX_ERROR)
    {
        return NGX_ERROR;
    }

    rc = 0;
    range = NULL;
    p = r->headers_in.range->value.data + 6;

    for ( ;; ) {
        start = 0;
        end = 0;
        suffix = 0;

        while (*p == ' ') { p++; }

        if (*p != '-') {
            if (*p < '0' || *p > '9') {
                rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
                break;
            }

            while (*p >= '0' && *p <= '9') {
                start = start * 10 + *p++ - '0';
            }

            while (*p == ' ') { p++; }

            if (*p++ != '-') {
                rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
                break;
            }

            if (start >= r->headers_out.content_length_n) {
                rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
                break;
            }

            while (*p == ' ') { p++; }

            if (*p == ',' || *p == '\0') {
                range = ngx_array_push(&ctx->ranges);
                if (range == NULL) {
                    return NGX_ERROR;
                }

                range->start = start;
                range->end = r->headers_out.content_length_n;

                if (*p++ != ',') {
                    break;
                }

                continue;
            }

        } else {
            suffix = 1;
            p++;
        }

        if (*p < '0' || *p > '9') {
            rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
            break;
        }

        while (*p >= '0' && *p <= '9') {
            end = end * 10 + *p++ - '0';
        }

        while (*p == ' ') { p++; }

        if (*p != ',' && *p != '\0') {
            rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
            break;
        }

        if (suffix) {
           start = r->headers_out.content_length_n - end;
           end = r->headers_out.content_length_n - 1;
        }

        if (start > end) {
            rc = NGX_HTTP_RANGE_NOT_SATISFIABLE;
            break;
        }

        range = ngx_array_push(&ctx->ranges);
        if (range == NULL) {
            return NGX_ERROR;
        }

        range->start = start;

        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;
        }

        if (*p++ != ',') {
            break;
        }
    }

    if (rc) {

        /* rc == NGX_HTTP_RANGE_NOT_SATISFIABLE */

        r->headers_out.status = rc;

        content_range = ngx_list_push(&r->headers_out.headers);
        if (content_range == NULL) {
            return NGX_ERROR;
        }

        r->headers_out.content_range = content_range;

        content_range->hash = 1;
        content_range->key.len = sizeof("Content-Range") - 1;
        content_range->key.data = (u_char *) "Content-Range";

        content_range->value.data = ngx_palloc(r->pool,
                                       sizeof("bytes */") - 1 + NGX_OFF_T_LEN);
        if (content_range->value.data == NULL) {
            return NGX_ERROR;
        }

        content_range->value.len = ngx_sprintf(content_range->value.data,
                                               "bytes */%O",
                                               r->headers_out.content_length_n)
                                   - content_range->value.data;

        ngx_http_clear_content_length(r);

        return rc;
    }

    ngx_http_set_ctx(r, ctx, ngx_http_range_body_filter_module);

    r->headers_out.status = NGX_HTTP_PARTIAL_CONTENT;

    if (ctx->ranges.nelts == 1) {

        content_range = ngx_list_push(&r->headers_out.headers);
        if (content_range == NULL) {
            return NGX_ERROR;
        }

        r->headers_out.content_range = content_range;

        content_range->hash = 1;
        content_range->key.len = sizeof("Content-Range") - 1;
        content_range->key.data = (u_char *) "Content-Range";

        content_range->value.data =
               ngx_palloc(r->pool, sizeof("bytes -/") - 1 + 3 * NGX_OFF_T_LEN);
        if (content_range->value.data == NULL) {
            return NGX_ERROR;
        }

        /* "Content-Range: bytes SSSS-EEEE/TTTT" header */

        content_range->value.len = ngx_sprintf(content_range->value.data,