diff options
Diffstat (limited to 'tileserver/tileserver.c')
| -rw-r--r-- | tileserver/tileserver.c | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/tileserver/tileserver.c b/tileserver/tileserver.c new file mode 100644 index 000000000..f64ff209f --- /dev/null +++ b/tileserver/tileserver.c @@ -0,0 +1,416 @@ +/* + * tileserver.c: + * Serve map tiles and information about map tiles. + * + * Copyright (c) 2006 UK Citizens Online Democracy. All rights reserved. + * Email: chris@mysociety.org; WWW: http://www.mysociety.org/ + * + */ + +static const char rcsid[] = "$Id: tileserver.c,v 1.1 2006-09-20 10:25:14 chris Exp $"; + +/* + * This is slightly complicated by the fact that we indirect tile references + * via hashes of the tiles themselves. We support the following queries: + * + * http://host/path/tileserver/TILESET/HASH + * to get an individual tile image in TILESET identified by HASH; + * http://host/path/tileserver/TILESET/E,N/FORMAT + * to get the identity of the tile at (E, N) in TILESET in the given + * FORMAT; + * http://host/path/tileserver/TILESET/W-E,S-N/FORMAT + * to get the identities of the tiles in the block with SW corner (W, S) + * and NE corner (E, N) in the given FORMAT. + * + * What FORMATS should we support? RABX and JSON are the obvious ones I guess. + */ + +#include "tileset.h" + +/* tileset_path + * The configured path to tilesets. */ +char *tileset_path; + +#define HTTP_BAD_REQUEST 400 +#define HTTP_UNAUTHORIZED 401 +#define HTTP_FORBIDDEN 403 +#define HTTP_NOT_FOUND 404 +#define HTTP_INTERNAL_SERVER_ERROR 500 +#define HTTP_NOT_IMPLEMENTED 501 +#define HTTP_SERVICE_UNAVAILABLE 503 + +/* err FORMAT [ARG ...] + * Write an error message to standard error. */ +#define err(...) \ + do { \ + fprintf(stderr, "tileserver: "); \ + fprintf(stderr, __VA_ARGS__); \ + fprintf(stderr, "\n"); \ + } while (0) + +/* die FORMAT [ARG ...] + * Write an error message to standard error and exit unsuccessfully. */ +#define die(...) do { err(__VA_ARGS__); exit(1); } while (0) + +/* error STATUS TEXT + * Send an error to the client with the given HTTP STATUS and TEXT. */ +void error(int status, const char *s) { + if (status < 100 || status > 999) + status = 500; + printf( + "Status: %03d\r\n" + "Content-Type: text/plain; charset=us-ascii\r\n" + "Content-Length: %u\r\n" + "\r\n" + "%s\n", + status, + strlen(s) + 1); +} + +/* struct request + * Definition of a request we handle. */ +struct request { + char *r_tileset; + enum { + FN_GET_TILE = 0, + FN_GET_TILEIDS + } r_function; + + uint8_t r_tilehash[TILEHASH_LEN]; + + int r_west, r_east, r_south, r_north; + enum { + F_RABX, + F_JSON, + F_TEXT + } r_format; + + char *r_buf; +}; + +/* request_parse PATHINFO + * Parse a request from PATHINFO. Returns a request on success or NULL on + * failure. */ +struct request *request_parse(const char *path_info) { + const char *p, *q; + struct request *R = NULL, Rz = {0}; + + /* Some trivial syntax checks. */ + if (!*path_info || *path_info == '/' || !strchr(path_info, '/')) + return NULL; + + + /* + * TILESET/HASH + * TILESET/E,N/FORMAT + * TILESET/W-E,S-N/FORMAT + */ + + /* Tileset name consists of alphanumerics and hyphen. */ + p = path_info + strspn(path_info, + "0123456789" + "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + "abcdefghijklmnopqrstuvwxyz" + "-"); + + if (*p != '/') + return NULL; + + R = xmalloc(sizeof *R); + *R = Rz; + R->r_buf = xmalloc(strlen(path_info) + 1); + R->r_tileset = R->r_buf; + + strncpy(R->r_tileset, path_info, p - path_info); + R->r_tileset[p - path_info] = 0; + + ++p; + + /* Mode. */ + if ((q = strchr(p, '/'))) { + /* Tile IDs request. */ + R->r_function = FN_GET_TILEIDS; + + /* Identify format requested. */ + ++q; + if (!strcmp(q, "RABX")) + R->r_format = F_RABX; + else if (!strcmp(q, "JSON")) + R->r_format = F_JSON; + else if (!strcmp(q, "text")) + R->r_format = F_TEXT; + else + goto fail; + + if (4 == sscanf(p, "%d-%d,%d-%d", + &R->r_west, &R->r_east, &R->r_south, &R->r_north)) { + if (R->r_west < 0 || R->r_south < 0 + || R->r_east < R->r_west || R->r_north < R->r_south) + goto fail; + else + return R; + } else if (2 == sscanf(p, "%d,%d", &R->r_west, &R->r_south)) { + R->r_east = R->r_west; + R->r_north = R->r_south; + if (R->r_west < 0 || R->r_south < 0) + goto fail; + else + return R; + } + } else { + size_t l; + + /* Tile request. */ + R->r_function = FN_GET_TILE; + if (strlen(p) != TILEID_LEN_B64) + goto fail; + + /* Decode it. Really this is "base64ish", so that we don't have to + * deal with '+' or '/' in the URL. */ + base64_decode(p, R->r_tilehash, &l, 1); + if (l != TILEID_LEN) + goto fail; + + return R; + } + +fail: + request_free(R); + return NULL; +} + +void request_free(struct request *R) { + if (!R) return; + xfree(R->r_buf); + xfree(R); +} + +void handle_request(void) { + char *path_info; + struct request *R; + static char *path; + static size_t pathlen; + size_t l; + tileset T; + time_t when; + struct tm tm; + char timebuf[32]; + + /* All requests are given via PATH_INFO. */ + if (!(path_info = getenv("PATH_INFO"))) { + error(400, "No request path supplied"); + return; + } + + if (!(R = request_parse(path_info))) { + error(400, "Bad request"); + return; + } + + /* So we have a valid request. */ + l = strlen(R->r_tileset) + strlen(tileset_path) + 2; + if (pathlen < l) + pathlen = xrealloc(path, pathlen = l); + sprintf(path, "%s/%s", tileset_path, R->r_tileset); + + if (!(T = tileset_open(path))) { + error(404, "Tileset not found"); + /* XXX assumption about the nature of the error */ + return; + } + + if (FN_GET_TILE == R->r_function) { + /* + * Send a single tile image to the client. + */ + void *buf; + size_t len; + + if ((buf = tileset_get_tile(T, T->r_tileid, &len))) { + printf( + "Content-Type: image/png\r\n" + "Content-Length: %u\r\n" + "\r\n"); + fwrite(stdout, 1, buf, len); + xfree(buf); + } else + error(404, "Tile not found"); + /* XXX error assumption */ + } else if (FN_GET_TILEIDS = R->r_function) { + /* + * Send one or more tile IDs to the client, in some useful format. + */ + unsigned x, y; + static char *buf; + static size_t buflen, n; + unsigned rows, cols; + char *p; + + rows = R->r_north + 1 - R->r_south; + cols = R->r_east + 1 - R->r_west; + n = cols * rows; + if (buflen < n * TILEID_LEN_B64 + 256) + buf = xrealloc(buf, buflen = n * TILEID_LEN_B64 + 256); + + /* Send start of array in whatever format. */ + p = buf; + switch (R->r_format) { + case F_RABX: + /* Format as array of arrays. */ + *(p++) = 'L'; + p += netstring_write_int(p, (int)rows); + break; + + case F_JSON: + /* Ditto. */ + *(p++) = '['; + break; + + case F_TEXT: + /* Space and LF separated matrix so no special leader. */ + break; + } + + /* Iterate over tile IDs. */ + for (y = R->r_south; y <= R->r_north; ++y) { + switch (R->r_format) { + case F_RABX: + *(p++) = 'L'; + p += netstring_write_int(p, (int)cols); + + case F_JSON: + *(p++) = '['; + + case F_TEXT: + break; /* nothing */ + } + + for (x = R->r_west; x <= R->r_east; ++x) { + uint8_t id[TILEID_LEN]; + char idb64[TILEID_LEN_B64 + 1]; + bool isnull = 0; + size_t l; + + if (!(tileset_get_tileid(T, x, y, id))) + isnull = 1; + else + base64_encode(id, TILEID_LEN, idb64, 1, 1); + + if (p + 256 > buflen) { + size_t n; + n = p - buf; + buf = xrealloc(buf, buflen *= 2); + p = buf + n; + } + + switch (R->r_format) { + case F_RABX: + if (isnull) { + *(p++) = 'T'; + p += netstring_write(p, idb64); + } else + *(p++) = 'N'; + break; + + case F_JSON: + if (isnull) { + strcpy(p, "null"); + p += 4; + } else { + *(p++) = '"'; + strcpy(p, idb64); + p += TILEID_LEN_B64; + *(p++) = '"'; + } + if (x < R->r_east) + *(p++) = ','; + break; + + case F_TEXT: + if (isnull) + *(p++) = '-'; + else { + strcpy(p, idb64); + p += TILEID_LEN_B64; + } + if (x < R->r_east) + *(p++) = ' '; + break; + } + } + + switch (R->r_format) { + case F_RABX: + break; /* no row terminator */ + + case F_JSON: + *(p++) = ']'; + if (y < R->r_north) + *(p++) = ','; + break; + + case F_TEXT: + *(p++) = '\n'; + break; + } + } + + /* Array terminator. */ + switch (R->r_format) { + case F_RABX: + break; + + case F_JSON: + *(p++) = ']'; + break; + + case F_TEXT: + *(p++) = '\n'; + break; + } + *(p++) = 0; + + /* Actually send it. */ + printf("Content-Type: "); + switch (R->r_format) { + case F_RABX: + printf("application/octet-stream"); + break; + + case F_JSON: + /* Not really clear what CT to use here but Yahoo use + * "text/javascript" and presumably they've done more testing + * than us.... */ + printf("text/javascript"); + break; + + case F_TEXT: + printf("text/plain; charset=us-ascii"); + break; + } + printf("\r\n" + "Content-Length: %u\r\n" + "\r\n", + (unsigned)(p - buf)); + + fwrite(buf, 1, p - buf, stdout); + } +} + +int main(int argc, char *argv[]) { + struct stat st; + + if (2 != argc) { + die("single argument is path to tile sets"); + } + tileset_path = argv[1]; + if (-1 == stat(tileset_path, &st)) + die("%s: stat: %s", tileset_path, strerror(errno)); + else if (!S_ISDIR(st.st_mode)) + die("%s: Not a directory", tileset_path); + + while (FCGI_Accept() >= 0) + handle_request(); + + return 0; +} |