EXPORT int mongo_gridfile_get_chunks(struct gridfile_* gf, int start, int count, struct mongo_cursor_** out) {
    mongo_cursor* cursor = gridfile_get_chunks((gridfile*)gf, start, count);
    if (!cursor)
        return 0;
    *out = (struct mongo_cursor_*)cursor;
    return 1;
}
Beispiel #2
0
SEXP mongo_gridfile_get_chunks(SEXP gfile, SEXP start, SEXP count) {
    gridfile* _gfile = _checkGridfile(gfile);
    int _start = asInteger(start);
    int _count = asInteger(count);
    mongo_cursor* cursor = gridfile_get_chunks(_gfile, _start, _count);
    return _mongo_cursor_create(cursor);
}
Beispiel #3
0
gridfs_offset gridfile_read(gridfile* gfile, gridfs_offset size, char* buf)

{
    mongo_cursor* chunks;
    bson chunk;

    int first_chunk;
    int last_chunk;
    int total_chunks;
    gridfs_offset chunksize;
    gridfs_offset contentlength;
    gridfs_offset bytes_left;
    int i;
    bson_iterator it;
    gridfs_offset chunk_len;
    const char * chunk_data;

    contentlength = gridfile_get_contentlength(gfile);
    chunksize = gridfile_get_chunksize(gfile);
    size = (contentlength - gfile->pos < size)
           ? contentlength - gfile->pos
           : size;
    bytes_left = size;

    first_chunk = (gfile->pos)/chunksize;
    last_chunk = (gfile->pos+size-1)/chunksize;
    total_chunks = last_chunk - first_chunk + 1;
    chunks = gridfile_get_chunks(gfile, first_chunk, total_chunks);

    for (i = 0; i < total_chunks; i++) {
        mongo_cursor_next(chunks);
        chunk = chunks->current;
        bson_find(&it, &chunk, "data");
        chunk_len = bson_iterator_bin_len( &it );
        chunk_data = bson_iterator_bin_data( &it );
        if (i == 0) {
            chunk_data += (gfile->pos)%chunksize;
            chunk_len -= (gfile->pos)%chunksize;
        }
        if (bytes_left > chunk_len) {
            memcpy(buf, chunk_data, chunk_len);
            bytes_left -= chunk_len;
            buf += chunk_len;
        } else {
            memcpy(buf, chunk_data, bytes_left);
        }
    }

    mongo_cursor_destroy(chunks);
    gfile->pos = gfile->pos + size;

    return size;
}
static ngx_int_t ngx_http_gridfs_handler(ngx_http_request_t* request) {
    ngx_http_gridfs_loc_conf_t* gridfs_conf;
    ngx_http_core_loc_conf_t* core_conf;
    ngx_buf_t* buffer;
    ngx_chain_t out;
    ngx_str_t location_name;
    ngx_str_t full_uri;
    char* value;
    ngx_http_mongo_connection_t *mongo_conn;
    gridfs gfs;
    gridfile gfile;
    gridfs_offset length;
    ngx_uint_t numchunks;
    char* contenttype;
    char* md5;
    bson_date_t last_modified;

    volatile ngx_uint_t i;
    ngx_int_t rc = NGX_OK;
    bson query;
    bson_oid_t oid;
    mongo_cursor ** cursors;
    gridfs_offset chunk_len;
    const char * chunk_data;
    bson_iterator it;
    bson chunk;
    ngx_pool_cleanup_t* gridfs_cln;
    ngx_http_gridfs_cleanup_t* gridfs_clndata;
    int status;
    volatile ngx_uint_t e = FALSE;
    volatile ngx_uint_t ecounter = 0;
    uint64_t range_start = 0;
    uint64_t range_end   = 0;
    uint64_t current_buf_pos = 0;

    gridfs_conf = ngx_http_get_module_loc_conf(request, ngx_http_gridfs_module);
    core_conf = ngx_http_get_module_loc_conf(request, ngx_http_core_module);

    // ---------- ENSURE MONGO CONNECTION ---------- //

    mongo_conn = ngx_http_get_mongo_connection( gridfs_conf->mongo );
    if (mongo_conn == NULL) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Mongo Connection not found: \"%V\"", &gridfs_conf->mongo);
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    if (mongo_conn->conn.connected == 0) {
        if (ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Could not connect to mongo: \"%V\"", &gridfs_conf->mongo);
            if(mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
            return NGX_HTTP_SERVICE_UNAVAILABLE;
        }
        if (ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to reauth to mongo: \"%V\"", &gridfs_conf->mongo);
            if(mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
            return NGX_HTTP_SERVICE_UNAVAILABLE;
        }
    }

    // ---------- RETRIEVE KEY ---------- //

    location_name = core_conf->name;
    full_uri = request->uri;

    if (full_uri.len < location_name.len) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Invalid location name or uri.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    value = (char*)malloc(sizeof(char) * (full_uri.len - location_name.len + 1));
    if (value == NULL) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Failed to allocate memory for value buffer.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    memcpy(value, full_uri.data + location_name.len, full_uri.len - location_name.len);
    value[full_uri.len - location_name.len] = '\0';

    if (!url_decode(value)) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Malformed request.");
        free(value);
        return NGX_HTTP_BAD_REQUEST;
    }

    // ---------- RETRIEVE GRIDFILE ---------- //

    bson_init(&query);
    switch (gridfs_conf->type) {
    case  BSON_OID:
        bson_oid_from_string(&oid, value);
        bson_append_oid(&query, (char*)gridfs_conf->field.data, &oid);
        break;
    case BSON_INT:
      bson_append_int(&query, (char*)gridfs_conf->field.data, ngx_atoi((u_char*)value, strlen(value)));
        break;
    case BSON_STRING:
        bson_append_string(&query, (char*)gridfs_conf->field.data, value);
        break;
    }
    bson_finish(&query);

    do {
        e = FALSE;
        if (gridfs_init(&mongo_conn->conn,
                        (const char*)gridfs_conf->db.data,
                        (const char*)gridfs_conf->root_collection.data,
                        &gfs) != MONGO_OK
            || (status = gridfs_find_query(&gfs, &query, &gfile) == MONGO_ERROR)) {
            e = TRUE; ecounter++;
            if (ecounter > MONGO_MAX_RETRIES_PER_REQUEST
                || ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR
                || ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR) {
                ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                              "Mongo connection dropped, could not reconnect");
                if(&mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
                bson_destroy(&query);
                free(value);
                return NGX_HTTP_SERVICE_UNAVAILABLE;
            }
        }
    } while (e);

    bson_destroy(&query);
    free(value);

    /* Get information about the file */
    length = gridfile_get_contentlength(&gfile);
    numchunks = gridfile_get_numchunks(&gfile);

    // NaN workaround
    if (numchunks > INT_MAX)
    {
        gridfile_destroy(&gfile);
        gridfs_destroy(&gfs);
        return NGX_HTTP_NOT_FOUND;
    }

    contenttype = (char*)gridfile_get_contenttype(&gfile);

    md5 = (char*)gridfile_get_md5(&gfile);
    last_modified = gridfile_get_uploaddate(&gfile);

    // ---------- Partial Range
    // set follow-fork-mode child
    // attach (pid)
    // break ngx_http_gridfs_module.c:959

    if (request->headers_in.range) {
        gridfs_parse_range(request, &request->headers_in.range->value, &range_start, &range_end, length);
    }

    // ---------- SEND THE HEADERS ---------- //

    if (range_start == 0 && range_end == 0) {
        request->headers_out.status = NGX_HTTP_OK;
        request->headers_out.content_length_n = length;
    } else {
        request->headers_out.status = NGX_HTTP_PARTIAL_CONTENT;
        request->headers_out.content_length_n = length;
        //request->headers_out.content_range = range_end - range_start + 1;

        ngx_table_elt_t   *content_range;

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

        request->headers_out.content_range = content_range;

        content_range->hash = 1;
        ngx_str_set(&content_range->key, "Content-Range");

        content_range->value.data = ngx_pnalloc(request->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,
                                               "bytes %O-%O/%O",
                                               range_start, range_end,
                                               request->headers_out.content_length_n)
            - content_range->value.data;

        request->headers_out.content_length_n = range_end - range_start + 1;
    }
    if (contenttype != NULL) {
        request->headers_out.content_type.len = strlen(contenttype);
        request->headers_out.content_type.data = (u_char*)contenttype;
    }
    else ngx_http_set_content_type(request);

    // use md5 field as ETag if possible
    if (md5 != NULL) {
        request->headers_out.etag = ngx_list_push(&request->headers_out.headers);
        request->headers_out.etag->hash = 1;
        request->headers_out.etag->key.len = sizeof("ETag") - 1;
        request->headers_out.etag->key.data = (u_char*)"ETag";

        ngx_buf_t *b;
        b = ngx_create_temp_buf(request->pool, strlen(md5) + 2);
        b->last = ngx_sprintf(b->last, "\"%s\"", md5);
        request->headers_out.etag->value.len = strlen(md5) + 2;
        request->headers_out.etag->value.data = b->start;
    }

    // use uploadDate field as last_modified if possible
    if (last_modified) {
        request->headers_out.last_modified_time = (time_t)(last_modified/1000);
    }

    /* Determine if content is gzipped, set headers accordingly */
    if ( gridfile_get_boolean(&gfile,"gzipped") ) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0, gridfile_get_field(&gfile,"gzipped") );
        request->headers_out.content_encoding = ngx_list_push(&request->headers_out.headers);
        if (request->headers_out.content_encoding == NULL) {
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_ERROR;
        }
        request->headers_out.content_encoding->hash = 1;
        request->headers_out.content_encoding->key.len = sizeof("Content-Encoding") - 1;
        request->headers_out.content_encoding->key.data = (u_char *) "Content-Encoding";
        request->headers_out.content_encoding->value.len = sizeof("gzip") - 1;
        request->headers_out.content_encoding->value.data = (u_char *) "gzip";
    }

    ngx_http_send_header(request);

    // ---------- SEND THE BODY ---------- //

    /* Empty file */
    if (numchunks == 0) {
        /* Allocate space for the response buffer */
        buffer = ngx_pcalloc(request->pool, sizeof(ngx_buf_t));
        if (buffer == NULL) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to allocate response buffer");
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

        buffer->pos = NULL;
        buffer->last = NULL;
        buffer->memory = 1;
        buffer->last_buf = 1;
        out.buf = buffer;
        out.next = NULL;

        gridfile_destroy(&gfile);
        gridfs_destroy(&gfs);

        return ngx_http_output_filter(request, &out);
    }

    cursors = (mongo_cursor **)ngx_pcalloc(request->pool, sizeof(mongo_cursor *) * numchunks);
    if (cursors == NULL) {
      gridfile_destroy(&gfile);
      gridfs_destroy(&gfs);
      return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    ngx_memzero( cursors, sizeof(mongo_cursor *) * numchunks);

    /* Hook in the cleanup function */
    gridfs_cln = ngx_pool_cleanup_add(request->pool, sizeof(ngx_http_gridfs_cleanup_t));
    if (gridfs_cln == NULL) {
      gridfile_destroy(&gfile);
      gridfs_destroy(&gfs);
      return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    gridfs_cln->handler = ngx_http_gridfs_cleanup;
    gridfs_clndata = gridfs_cln->data;
    gridfs_clndata->cursors = cursors;
    gridfs_clndata->numchunks = numchunks;

    /* Read and serve chunk by chunk */
    for (i = 0; i < numchunks; i++) {

        /* Allocate space for the response buffer */
        buffer = ngx_pcalloc(request->pool, sizeof(ngx_buf_t));
        if (buffer == NULL) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to allocate response buffer");
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

        /* Fetch the chunk from mongo */
        do {
            e = FALSE;
            cursors[i] = gridfile_get_chunks(&gfile, i, 1);
            if (!(cursors[i] && mongo_cursor_next(cursors[i]) == MONGO_OK)) {
                e = TRUE; ecounter++;
                if (ecounter > MONGO_MAX_RETRIES_PER_REQUEST
                    || ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR
                    || ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR) {
                    ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                                  "Mongo connection dropped, could not reconnect");
                    if(mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
                    gridfile_destroy(&gfile);
                    gridfs_destroy(&gfs);
                    return NGX_HTTP_SERVICE_UNAVAILABLE;
                }
            }
        } while (e);

        chunk = cursors[i]->current;
        bson_find(&it, &chunk, "data");
        chunk_len = bson_iterator_bin_len( &it ); // break ngx_http_gridfs_module.c:1099
        chunk_data = bson_iterator_bin_data( &it );

        if (range_start == 0 && range_end == 0) {
            /* <<no range request>> */
            /* Set up the buffer chain */
            buffer->pos = (u_char*)chunk_data;
            buffer->last = (u_char*)chunk_data + chunk_len;
            buffer->memory = 1;
            buffer->last_buf = (i == numchunks-1);
            out.buf = buffer;
            out.next = NULL;

            /* Serve the Chunk */
            rc = ngx_http_output_filter(request, &out);
        } else {
            /* <<range request>> */
            if ( range_start >= (current_buf_pos+chunk_len) ||
                 range_end <= current_buf_pos) {
                /* no output */
                ngx_pfree(request->pool, buffer);
            } else {
                if (range_start <= current_buf_pos) {
                    buffer->pos = (u_char*)chunk_data;
                } else {
                    buffer->pos = (u_char*)chunk_data + (range_start - current_buf_pos);
                }
                if (range_end < (current_buf_pos+chunk_len)) {
                    buffer->last = (u_char*)chunk_data + (range_end - current_buf_pos + 1);
                } else {
                    buffer->last = (u_char*)chunk_data + chunk_len;
                }
                if (buffer->pos == buffer->last) {
                    ngx_log_error(NGX_LOG_ALERT, request->connection->log, 0,
                                  "zero size buf in writer "
                                  "range_start:%d range_end:%d "
                                  "current_buf_pos:%d chunk_len:%d i:%d numchunk:%d",
                                  range_start,range_end,
                                  current_buf_pos, chunk_len,
                                  i,numchunks);
                }
                buffer->memory = 1;
                buffer->last_buf = (i == numchunks-1) || (range_end < (current_buf_pos+chunk_len));
                out.buf = buffer;
                out.next = NULL;

                /* Serve the Chunk */
                rc = ngx_http_output_filter(request, &out);
            }
        }

        current_buf_pos += chunk_len;

        /* TODO: More Codes to Catch? */
        if (rc == NGX_ERROR) {
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_ERROR;
        }
    }

    gridfile_destroy(&gfile);
    gridfs_destroy(&gfs);

    return rc;
}
static ngx_int_t ngx_http_gridfs_handler(ngx_http_request_t* request) {
    ngx_http_gridfs_loc_conf_t* gridfs_conf;
    ngx_http_core_loc_conf_t* core_conf;
    ngx_buf_t* buffer;
    ngx_chain_t out;
    ngx_str_t location_name;
    ngx_str_t full_uri;
    // --------------- xulin add start -------------------
    char* ml_args;
    char* arg;
    unsigned int add_arg;
    unsigned int add_len; 
    // --------------- xulin add end -------------------
    char* value;
    ngx_http_mongo_connection_t *mongo_conn;
    gridfs gfs;
    gridfile gfile;
    gridfs_offset length;
    ngx_uint_t numchunks;
    char* contenttype;
    char* md5;
    bson_date_t last_modified;

    volatile ngx_uint_t i;
    ngx_int_t rc = NGX_OK;
    bson query;
    bson_oid_t oid;
    mongo_cursor ** cursors;
    gridfs_offset chunk_len;
    const char * chunk_data;
    bson_iterator it;
    bson chunk;
    ngx_pool_cleanup_t* gridfs_cln;
    ngx_http_gridfs_cleanup_t* gridfs_clndata;
    int status;
    volatile ngx_uint_t e = FALSE; 
    volatile ngx_uint_t ecounter = 0;

    gridfs_conf = ngx_http_get_module_loc_conf(request, ngx_http_gridfs_module);
    core_conf = ngx_http_get_module_loc_conf(request, ngx_http_core_module);

    // ---------- ENSURE MONGO CONNECTION ---------- //

    mongo_conn = ngx_http_get_mongo_connection( gridfs_conf->mongo );
    if (mongo_conn == NULL) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Mongo Connection not found: \"%V\"", &gridfs_conf->mongo);
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    
    if ( !(&mongo_conn->conn.connected)
         && (ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR
             || ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR)) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Could not connect to mongo: \"%V\"", &gridfs_conf->mongo);
        if(&mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
        return NGX_HTTP_SERVICE_UNAVAILABLE;
    }

    // ---------- RETRIEVE KEY ---------- //

    location_name = core_conf->name;
    full_uri = request->uri;

    if (full_uri.len < location_name.len) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Invalid location name or uri.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    value = (char*)malloc(sizeof(char) * (full_uri.len - location_name.len + 1 + request->args.len + 1));
    if (value == NULL) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Failed to allocate memory for value buffer.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    memcpy(value, full_uri.data + location_name.len, full_uri.len - location_name.len);
    
    // ------------------------------------ xulin add start --------------------------------------
    if (request->args.len > 0)
    {  
        ml_args = (char*)malloc(sizeof(char) * (request->args.len + 1));
        memcpy(ml_args, request->args.data, request->args.len);
        ml_args[request->args.len] = '\0';
        
        add_len = full_uri.len - location_name.len;
        memcpy(value + add_len, "?", 1);
        add_len += 1;
        arg = strtok(ml_args, "&");
        while (arg != NULL)
        {
            add_arg = 1;
            if (strstr(arg, "xc_md5") != NULL)
            {
                 add_arg = 0;
            }
            else if (strstr(arg, "_xingcloud_t") != NULL)
            {     
                 add_arg = 0;
            }        
            
            if (add_arg == 1)
            {
                 memcpy(value + add_len, arg, strlen(arg));
                 add_len += strlen(arg);
                 memcpy(value + add_len, "&", 1);
                 add_len += 1;
            }
            
            arg = strtok(NULL, "&");
        }
        
        free(ml_args);
        if (value[add_len - 1] == '?' || value[add_len - 1] == '&')
        {
            value[add_len - 1] = '\0';
        }
        else
        {
            value[add_len] = '\0';
        }
    }
    ngx_log_error(NGX_LOG_ERR, request->connection->log, 0, "ml_url = [%s]", value);
    // ------------------------------------ xulin add end --------------------------------------


    if (!url_decode(value)) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Malformed request.");
        free(value);
        return NGX_HTTP_BAD_REQUEST;
    }

    // ---------- RETRIEVE GRIDFILE ---------- //

    do {
        e = FALSE;
        if (gridfs_init(&mongo_conn->conn,
                        (const char*)gridfs_conf->db.data,
                        (const char*)gridfs_conf->root_collection.data,
                        &gfs) != MONGO_OK) {
            e = TRUE; ecounter++;
            if (ecounter > MONGO_MAX_RETRIES_PER_REQUEST
                || ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR
                || ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR) {
                ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                              "Mongo connection dropped, could not reconnect");
                if(&mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
                free(value);
                return NGX_HTTP_SERVICE_UNAVAILABLE;
            }
        }
    } while (e);

    bson_init(&query);
    switch (gridfs_conf->type) {
    case  BSON_OID:
        bson_oid_from_string(&oid, value);
        bson_append_oid(&query, (char*)gridfs_conf->field.data, &oid);
        break;
    case BSON_INT:
      bson_append_int(&query, (char*)gridfs_conf->field.data, ngx_atoi((u_char*)value, strlen(value)));
        break;
    case BSON_STRING:
        bson_append_string(&query, (char*)gridfs_conf->field.data, value);
        break;
    }
    bson_finish(&query);

    status = gridfs_find_query(&gfs, &query, &gfile);
    
    bson_destroy(&query);
    free(value);

    if(status == MONGO_ERROR) {
        gridfs_destroy(&gfs);
        return NGX_HTTP_NOT_FOUND;
    }

    /* Get information about the file */
    length = gridfile_get_contentlength(&gfile);
    numchunks = gridfile_get_numchunks(&gfile);
    contenttype = (char*)gridfile_get_contenttype(&gfile);

    md5 = (char*)gridfile_get_md5(&gfile);
    last_modified = gridfile_get_uploaddate(&gfile);

    // ---------- SEND THE HEADERS ---------- //

    request->headers_out.status = NGX_HTTP_OK;
    request->headers_out.content_length_n = length;
    if (contenttype != NULL) {
        request->headers_out.content_type.len = strlen(contenttype);
        request->headers_out.content_type.data = (u_char*)contenttype;
    }
    else ngx_http_set_content_type(request);

    // use md5 field as ETag if possible
    if (md5 != NULL) {
        request->headers_out.etag = ngx_list_push(&request->headers_out.headers);
        request->headers_out.etag->hash = 1;
        request->headers_out.etag->key.len = sizeof("ETag") - 1;
        request->headers_out.etag->key.data = (u_char*)"ETag";

        ngx_buf_t *b;  
        b = ngx_create_temp_buf(request->pool, strlen(md5) + 2);  
        b->last = ngx_sprintf(b->last, "\"%s\"", md5);
        request->headers_out.etag->value.len = strlen(md5) + 2;
        request->headers_out.etag->value.data = b->start;
    }
    
    // use uploadDate field as last_modified if possible
    if (last_modified) {
        request->headers_out.last_modified_time = (time_t)(last_modified/1000);
    }

    /* Determine if content is gzipped, set headers accordingly */
    if ( gridfile_get_boolean(&gfile,"gzipped") ) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0, gridfile_get_field(&gfile,"gzipped") );
        request->headers_out.content_encoding = ngx_list_push(&request->headers_out.headers);
        if (request->headers_out.content_encoding == NULL) {
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_ERROR;
        }
        request->headers_out.content_encoding->hash = 1;
        request->headers_out.content_encoding->key.len = sizeof("Content-Encoding") - 1;
        request->headers_out.content_encoding->key.data = (u_char *) "Content-Encoding";
        request->headers_out.content_encoding->value.len = sizeof("gzip") - 1;
        request->headers_out.content_encoding->value.data = (u_char *) "gzip";
    }

    ngx_http_send_header(request);

    // ---------- SEND THE BODY ---------- //

    /* Empty file */
    if (numchunks == 0) {
        /* Allocate space for the response buffer */
        buffer = ngx_pcalloc(request->pool, sizeof(ngx_buf_t));
        if (buffer == NULL) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to allocate response buffer");
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

        buffer->pos = NULL;
        buffer->last = NULL;
        buffer->memory = 1;
        buffer->last_buf = 1;
        out.buf = buffer;
        out.next = NULL;

        gridfile_destroy(&gfile);
        gridfs_destroy(&gfs);

        return ngx_http_output_filter(request, &out);
    }
    
    cursors = (mongo_cursor **)ngx_pcalloc(request->pool, sizeof(mongo_cursor *) * numchunks);
    if (cursors == NULL) {
      gridfile_destroy(&gfile);
      gridfs_destroy(&gfs);
      return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    
    ngx_memzero( cursors, sizeof(mongo_cursor *) * numchunks);

    /* Hook in the cleanup function */
    gridfs_cln = ngx_pool_cleanup_add(request->pool, sizeof(ngx_http_gridfs_cleanup_t));
    if (gridfs_cln == NULL) {
      gridfile_destroy(&gfile);
      gridfs_destroy(&gfs);
      return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    gridfs_cln->handler = ngx_http_gridfs_cleanup;
    gridfs_clndata = gridfs_cln->data;
    gridfs_clndata->cursors = cursors;
    gridfs_clndata->numchunks = numchunks;

    /* Read and serve chunk by chunk */
    for (i = 0; i < numchunks; i++) {

        /* Allocate space for the response buffer */
        buffer = ngx_pcalloc(request->pool, sizeof(ngx_buf_t));
        if (buffer == NULL) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to allocate response buffer");
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

        /* Fetch the chunk from mongo */
        do {
            e = FALSE;
            cursors[i] = gridfile_get_chunks(&gfile, i, 1);
            if (!(cursors[i] && mongo_cursor_next(cursors[i]) == MONGO_OK)) {
                e = TRUE; ecounter++;
                if (ecounter > MONGO_MAX_RETRIES_PER_REQUEST 
                    || ngx_http_mongo_reconnect(request->connection->log, mongo_conn) == NGX_ERROR
                    || ngx_http_mongo_reauth(request->connection->log, mongo_conn) == NGX_ERROR) {
                    ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                                  "Mongo connection dropped, could not reconnect");
                    if(&mongo_conn->conn.connected) { mongo_disconnect(&mongo_conn->conn); }
                    gridfile_destroy(&gfile);
                    gridfs_destroy(&gfs);
                    return NGX_HTTP_SERVICE_UNAVAILABLE;
                }
            }
        } while (e);

        chunk = cursors[i]->current;
        bson_find(&it, &chunk, "data");
        chunk_len = bson_iterator_bin_len( &it );
        chunk_data = bson_iterator_bin_data( &it );

        /* Set up the buffer chain */
        buffer->pos = (u_char*)chunk_data;
        buffer->last = (u_char*)chunk_data + chunk_len;
        buffer->memory = 1;
        buffer->last_buf = (i == numchunks-1);
        out.buf = buffer;
        out.next = NULL;

        /* Serve the Chunk */
        rc = ngx_http_output_filter(request, &out);

        /* TODO: More Codes to Catch? */
        if (rc == NGX_ERROR) {
            gridfile_destroy(&gfile);
            gridfs_destroy(&gfs);
            return NGX_ERROR;
        }
    }

    gridfile_destroy(&gfile);
    gridfs_destroy(&gfs);

    return rc;
}
static ngx_int_t ngx_http_gridfs_handler(ngx_http_request_t* request) {
    ngx_http_gridfs_loc_conf_t* gridfs_conf;
    ngx_http_core_loc_conf_t* core_conf;
    ngx_buf_t* buffer;
    ngx_chain_t out;
    ngx_str_t location_name;
    ngx_str_t full_uri;
    char* value;
    gridfs gfs;
    gridfile gfile;
    gridfs_offset length;
    ngx_uint_t chunksize;
    ngx_uint_t numchunks;
    char* contenttype;
    ngx_uint_t i;
    ngx_int_t rc = NGX_OK;
    bson query;
    bson_buffer buf;
    bson_oid_t oid;
    mongo_cursor ** cursors;
    gridfs_offset chunk_len;
    const char * chunk_data;
    bson_iterator it;
    bson chunk;
    ngx_pool_cleanup_t* gridfs_cln;
    ngx_http_gridfs_cleanup_t* gridfs_clndata;

    gridfs_conf = ngx_http_get_module_loc_conf(request, ngx_http_gridfs_module);
    core_conf = ngx_http_get_module_loc_conf(request, ngx_http_core_module);

    location_name = core_conf->name;
    full_uri = request->uri;

    gridfs_cln = ngx_pool_cleanup_add(request->pool, sizeof(ngx_http_gridfs_cleanup_t));
    if (gridfs_cln == NULL) {
      return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    gridfs_cln->handler = ngx_http_gridfs_cleanup;
    gridfs_clndata = gridfs_cln->data;

    /* defensive */
    if (full_uri.len < location_name.len) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Invalid location name or uri.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    /* Extract the value from the uri */
    value = (char*)malloc(sizeof(char) * (full_uri.len - location_name.len + 1));
    if (value == NULL) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Failed to allocate memory for value buffer.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    memcpy(value, full_uri.data + location_name.len, full_uri.len - location_name.len);
    value[full_uri.len - location_name.len] = '\0';

    /* URL Decoding */
    if (!url_decode(value)) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                      "Malformed request.");
        free(value);
        return NGX_HTTP_BAD_REQUEST;
    }

    /* Find the GridFile */
    gridfs_init(gridfs_conf->mongod_conn,
                (const char*)gridfs_conf->gridfs_db.data,
                (const char*)gridfs_conf->gridfs_root_collection.data,
                &gfs);
    bson_buffer_init(&buf);
    switch (gridfs_conf->gridfs_type) {
    case  bson_oid:
        bson_oid_from_string(&oid, value);
        bson_append_oid(&buf, (char*)gridfs_conf->gridfs_field.data, &oid);
        break;
    case bson_int:
      bson_append_int(&buf, (char*)gridfs_conf->gridfs_field.data, ngx_atoi((u_char*)value, strlen(value)));
        break;
    case bson_string:
        bson_append_string(&buf, (char*)gridfs_conf->gridfs_field.data, value);
        break;
    }
    bson_from_buffer(&query, &buf);
    if(!gridfs_find_query(&gfs, &query, &gfile)){
        bson_destroy(&query);
        free(value);
        return NGX_HTTP_NOT_FOUND;
    }
    bson_destroy(&query);
    free(value);

    /* Get information about the file */
    length = gridfile_get_contentlength(&gfile);
    chunksize = gridfile_get_chunksize(&gfile);
    numchunks = gridfile_get_numchunks(&gfile);
    contenttype = (char*)gridfile_get_contenttype(&gfile);

    /* Set the headers */
    request->headers_out.status = NGX_HTTP_OK;
    request->headers_out.content_length_n = length;
    if (contenttype != NULL) {
        request->headers_out.content_type.len = strlen(contenttype);
        request->headers_out.content_type.data = (u_char*)contenttype;
    }
    else ngx_http_set_content_type(request);

    /* Determine if content is gzipped, set headers accordingly */
    if ( gridfile_get_boolean(&gfile,"gzipped") ) {
        ngx_log_error(NGX_LOG_ERR, request->connection->log, 0, gridfile_get_field(&gfile,"gzipped") );
        request->headers_out.content_encoding = ngx_list_push(&request->headers_out.headers);
        if (request->headers_out.content_encoding == NULL) {
            return NGX_ERROR;
        }
        request->headers_out.content_encoding->hash = 1;
        request->headers_out.content_encoding->key.len = sizeof("Content-Encoding") - 1;
        request->headers_out.content_encoding->key.data = (u_char *) "Content-Encoding";
        request->headers_out.content_encoding->value.len = sizeof("gzip") - 1;
        request->headers_out.content_encoding->value.data = (u_char *) "gzip";
    }

    ngx_http_send_header(request);

    if (numchunks == 0) {
        /* Allocate space for the response buffer */
        buffer = ngx_pcalloc(request->pool, sizeof(ngx_buf_t));
        if (buffer == NULL) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to allocate response buffer");
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }
	
	buffer->pos = NULL;
	buffer->last = NULL;
	buffer->memory = 1;
	buffer->last_buf = 1;
	out.buf = buffer;
	out.next = NULL;
	return ngx_http_output_filter(request, &out);
    }
    
    cursors = (mongo_cursor **)ngx_pcalloc(request->pool, sizeof(mongo_cursor *) * numchunks);

    /* Read and serve chunk by chunk */
    for (i = 0; i < numchunks; i++) {

        /* Allocate space for the response buffer */
        buffer = ngx_pcalloc(request->pool, sizeof(ngx_buf_t));
        if (buffer == NULL) {
            ngx_log_error(NGX_LOG_ERR, request->connection->log, 0,
                          "Failed to allocate response buffer");
            return NGX_HTTP_INTERNAL_SERVER_ERROR;
        }

	/* Fetch the chunk from mongo */
	cursors[i] = gridfile_get_chunks(&gfile, i, 1);
	mongo_cursor_next(cursors[i]);
	chunk = cursors[i]->current;
	bson_find(&it, &chunk, "data");
	chunk_len = bson_iterator_bin_len( &it );
	chunk_data = bson_iterator_bin_data( &it );

        /* Set up the buffer chain */
        buffer->pos = (u_char*)chunk_data;
        buffer->last = (u_char*)chunk_data + chunk_len;
        buffer->memory = 1;
        buffer->last_buf = (i == numchunks-1);
        out.buf = buffer;
        out.next = NULL;

        /* Serve the Chunk */
        rc = ngx_http_output_filter(request, &out);

        /* TODO: More Codes to Catch? */
        if (rc == NGX_ERROR) {
            return NGX_ERROR;
        }
    }

    gridfs_clndata->cursors = cursors;
    gridfs_clndata->numchunks = numchunks;

    return rc;
}