netcdf-c/oc2/ochttp.c
Dennis Heimbigner 724128ad3b Add hack to deal with DAP2 signed byte hack.
re: issue https://github.com/Unidata/netcdf-c/issues/1316

The DAP2 data model does not have a signed byte type,
but netcdf-3 does have (only) a signed byte type.
So, when converting a netcdf-3 signed byte typed variable to
a DAP2 unsigned byte, the following actions are taken by thredds:
1. The variable type is marked as DAP2 (unsigned) byte.
2. A special attribute, "_Unsigned=false" is set for the variable
3. The corresponding "_FillValue" attribute, if any, is up-converted
   to the DAP2 Int16 type in order to hold, with sign, any signed byte
   fill value.

On the netcdf-c side, this looks like a fillvalue type mismatch and causes
an error. Instead, the netcdf-c dap2 conversion code needs to recognize
this hack and undo it locally.

So this change looks for the above case, and if found, then it properly
converts the _FillValue type to netcdf-3 signed byte.

Since DAP2 supports both signed and unsigned integers of sizes 16 and 32 bits,
this should be the only hack needed (famous last words).

It may later be desirable for the thredds DAP2 converter to modify its
behavior as well.
2019-02-13 14:36:14 -07:00

351 lines
8.9 KiB
C

/* Copyright 2018, UCAR/Unidata and OPeNDAP, Inc.
See the COPYRIGHT file for more information. */
#include "config.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "ocinternal.h"
#include "ocdebug.h"
#include "ochttp.h"
static size_t WriteFileCallback(void*, size_t, size_t, void*);
static size_t WriteMemoryCallback(void*, size_t, size_t, void*);
struct Fetchdata {
FILE* stream;
size_t size;
};
long
ocfetchhttpcode(CURL* curl)
{
long httpcode = 200;
CURLcode cstat = CURLE_OK;
/* Extract the http code */
cstat = CURLERR(curl_easy_getinfo(curl,CURLINFO_RESPONSE_CODE,&httpcode));
if(cstat != CURLE_OK) httpcode = 0;
return httpcode;
}
OCerror
ocfetchurl_file(CURL* curl, const char* url, FILE* stream,
off_t* sizep, long* filetime)
{
int stat = OC_NOERR;
CURLcode cstat = CURLE_OK;
struct Fetchdata fetchdata;
/* Set the URL */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_URL, (void*)url));
if (cstat != CURLE_OK)
goto fail;
/* send all data to this function */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteFileCallback));
if (cstat != CURLE_OK)
goto fail;
/* we pass our file to the callback function */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&fetchdata));
if (cstat != CURLE_OK)
goto fail;
/* One last thing; always try to get the last modified time */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_FILETIME, (long)1));
if (cstat != CURLE_OK)
goto fail;
fetchdata.stream = stream;
fetchdata.size = 0;
cstat = CURLERR(curl_easy_perform(curl));
if (cstat != CURLE_OK)
goto fail;
if (stat == OC_NOERR) {
/* return the file size*/
#ifdef OCDEBUG
oclog(OCLOGNOTE,"filesize: %lu bytes",fetchdata.size);
#endif
if (sizep != NULL)
*sizep = fetchdata.size;
/* Get the last modified time */
if(filetime != NULL)
cstat = curl_easy_getinfo(curl,CURLINFO_FILETIME,filetime);
if(cstat != CURLE_OK) goto fail;
}
return OCTHROW(stat);
fail:
nclog(NCLOGERR, "curl error: %s", curl_easy_strerror(cstat));
return OCTHROW(OC_ECURL);
}
OCerror
ocfetchurl(CURL* curl, const char* url, NCbytes* buf, long* filetime)
{
OCerror stat = OC_NOERR;
CURLcode cstat = CURLE_OK;
size_t len;
long httpcode = 0;
/* Set the URL */
cstat = CURLERR(CURLERR(curl_easy_setopt(curl, CURLOPT_URL, (void*)url)));
if (cstat != CURLE_OK)
goto fail;
/* send all data to this function */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback));
if (cstat != CURLE_OK)
goto fail;
/* we pass our file to the callback function */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void*)buf));
if (cstat != CURLE_OK)
goto fail;
/* One last thing; always try to get the last modified time */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_FILETIME, (long)1));
cstat = CURLERR(curl_easy_perform(curl));
if(cstat == CURLE_PARTIAL_FILE) {
/* Log it but otherwise ignore */
nclog(NCLOGWARN, "curl error: %s; ignored",
curl_easy_strerror(cstat));
cstat = CURLE_OK;
}
httpcode = ocfetchhttpcode(curl);
if(cstat != CURLE_OK) goto fail;
/* Get the last modified time */
if(filetime != NULL)
cstat = CURLERR(curl_easy_getinfo(curl,CURLINFO_FILETIME,filetime));
if(cstat != CURLE_OK) goto fail;
/* Null terminate the buffer*/
len = ncbyteslength(buf);
ncbytesappend(buf, '\0');
ncbytessetlength(buf, len); /* don't count null in buffer size*/
#ifdef OCDEBUG
nclog(NCLOGNOTE,"buffersize: %lu bytes",(off_t)ncbyteslength(buf));
#endif
return OCTHROW(stat);
fail:
nclog(NCLOGERR, "curl error: %s", curl_easy_strerror(cstat));
switch (httpcode) {
case 400: stat = OC_EBADURL; break;
case 401: stat = OC_EAUTH; break;
case 404: stat = OC_ENOFILE; break;
case 500: stat = OC_EDAPSVC; break;
case 200: break;
default: stat = OC_ECURL; break;
}
return OCTHROW(stat);
}
static size_t
WriteFileCallback(void* ptr, size_t size, size_t nmemb, void* data)
{
size_t realsize = size * nmemb;
size_t count;
struct Fetchdata* fetchdata;
fetchdata = (struct Fetchdata*) data;
if(realsize == 0)
nclog(NCLOGWARN,"WriteFileCallback: zero sized chunk");
count = fwrite(ptr, size, nmemb, fetchdata->stream);
if (count > 0) {
fetchdata->size += (count * size);
} else {
nclog(NCLOGWARN,"WriteFileCallback: zero sized write");
}
#ifdef OCPROGRESS
nclog(NCLOGNOTE,"callback: %lu bytes",(off_t)realsize);
#endif
return count;
}
static size_t
WriteMemoryCallback(void *ptr, size_t size, size_t nmemb, void *data)
{
size_t realsize = size * nmemb;
NCbytes* buf = (NCbytes*) data;
if(realsize == 0)
nclog(NCLOGWARN,"WriteMemoryCallback: zero sized chunk");
/* Optimize for reading potentially large dods datasets */
if(!ncbytesavail(buf,realsize)) {
/* double the size of the packet */
ncbytessetalloc(buf,2*ncbytesalloc(buf));
}
ncbytesappendn(buf, ptr, realsize);
#ifdef OCPROGRESS
nclog(NCLOGNOTE,"callback: %lu bytes",(off_t)realsize);
#endif
return realsize;
}
#if 0
static void
assembleurl(DAPURL* durl, NCbytes* buf, int what)
{
encodeurltext(durl->url,buf);
if(what & WITHPROJ) {
ncbytescat(buf,"?");
encodeurltext(durl->projection,buf);
}
if(what & WITHSEL) encodeurltext(durl->selection,buf);
}
static char mustencode="";
static char hexchars[16] = {
'0', '1', '2', '3',
'4', '5', '6', '7',
'8', '9', 'a', 'b',
'c', 'd', 'e', 'f',
};
static void
encodeurltext(char* text, NCbytes* buf)
{
/* Encode the URL to handle illegal characters */
len = strlen(url);
encoded = ocmalloc(len*4+1); /* should never be larger than this*/
if(encoded==NULL) return;
p = url; q = encoded;
while((c=*p++)) {
if(strchr(mustencode,c) != NULL) {
char tmp[8];
int hex1, hex2;
hex1 = (c & 0x0F);
hex2 = (c & 0xF0) >> 4;
tmp[0] = '0'; tmp[1] = 'x';
tmp[2] = hexchars[hex2]; tmp[3] = hexchars[hex1];
tmp[4] = '\0';
ncbytescat(buf,tmp);
} else *q++ = (char)c;
}
}
#endif
OCerror
occurlopen(CURL** curlp)
{
int stat = OC_NOERR;
CURLcode cstat = CURLE_OK;
CURL* curl;
/* initialize curl*/
curl = curl_easy_init();
if (curl == NULL)
stat = OC_ECURL;
else {
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1));
if (cstat != CURLE_OK)
stat = OC_ECURL;
}
if (curlp)
*curlp = curl;
return OCTHROW(stat);
}
void
occurlclose(CURL* curl)
{
if (curl != NULL)
curl_easy_cleanup(curl);
}
OCerror
ocfetchlastmodified(CURL* curl, char* url, long* filetime)
{
int stat = OC_NOERR;
CURLcode cstat = CURLE_OK;
/* Set the URL */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_URL, (void*)url));
if (cstat != CURLE_OK)
goto fail;
/* Ask for head */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_TIMEOUT, 30)); /* 30sec timeout*/
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 2));
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_HEADER, 1));
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_NOBODY, 1));
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1));
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_FILETIME, (long)1));
cstat = CURLERR(curl_easy_perform(curl));
if(cstat != CURLE_OK) goto fail;
if(filetime != NULL)
cstat = CURLERR(curl_easy_getinfo(curl,CURLINFO_FILETIME,filetime));
if(cstat != CURLE_OK) goto fail;
return OCTHROW(stat);
fail:
nclog(NCLOGERR, "curl error: %s", curl_easy_strerror(cstat));
return OCTHROW(OC_ECURL);
}
OCerror
ocping(const char* url)
{
int stat = OC_NOERR;
CURLcode cstat = CURLE_OK;
CURL* curl = NULL;
NCbytes* buf = NULL;
/* Create a CURL instance */
stat = occurlopen(&curl);
if(stat != OC_NOERR) return stat;
/* Use redirects */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 10L));
if (cstat != CURLE_OK)
goto done;
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L));
if (cstat != CURLE_OK)
goto done;
/* use a very short timeout: 5 seconds */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_TIMEOUT, (long)5));
if (cstat != CURLE_OK)
goto done;
/* fail on HTTP 400 code errors */
cstat = CURLERR(curl_easy_setopt(curl, CURLOPT_FAILONERROR, (long)1));
if (cstat != CURLE_OK)
goto done;
/* Try to get the file */
buf = ncbytesnew();
stat = ocfetchurl(curl,url,buf,NULL);
if(stat == OC_NOERR) {
/* Don't trust curl to return an error when request gets 404 */
long http_code = 0;
cstat = CURLERR(curl_easy_getinfo(curl,CURLINFO_RESPONSE_CODE, &http_code));
if (cstat != CURLE_OK)
goto done;
if(http_code >= 400) {
cstat = CURLE_HTTP_RETURNED_ERROR;
goto done;
}
} else
goto done;
done:
ncbytesfree(buf);
occurlclose(curl);
if(cstat != CURLE_OK) {
nclog(NCLOGERR, "curl error: %s", curl_easy_strerror(cstat));
stat = OC_EDAPSVC;
}
return OCTHROW(stat);
}