libidav/resource.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2015 Olaf Wintermann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libxml/tree.h>

#include "utils.h"
#include "session.h"
#include "methods.h"
#include "crypto.h"
#include "ucx/buffer.h"
#include "ucx/utils.h"

#include "resource.h"
#include "davqlexec.h"

#define xstreq(a,b) xmlStrEqual(BAD_CAST a, BAD_CAST b)

DavResource* dav_resource_new(DavSession *sn, char *path) {
    //char *href = util_url_path(url);
    //DavResource *res = dav_resource_new_href(sn, href);
    char *parent = util_parent_path(path);
    char *name = util_resource_name(path); 
    char *href = dav_session_create_plain_href(sn, path);
    
    DavResource *res = dav_resource_new_full(sn, parent, name, href);
    free(parent);
    return res;
}

DavResource* dav_resource_new_child(DavSession *sn, DavResource *parent, char *name) {
    char *path = util_concat_path(parent->path, name);
    char *href = dav_session_create_plain_href(sn, path);
    DavResource *res = dav_resource_new_full(sn, parent->path, name, href);
    free(path);
    return res;
}


DavResource* dav_resource_new_href(DavSession *sn, char *href) {  
    DavResource *res = ucx_mempool_calloc(sn->mp, 1, sizeof(DavResource));
    res->session = sn;
    
    // set name, path and href
    resource_set_info(res, href);
    
    // initialize resource data
    res->data = resource_data_new(sn);
    
    return res;
}

DavResource* dav_resource_new_full(DavSession *sn, char *parent_path, char *name, char *href) {
    DavResource *res = ucx_mempool_calloc(sn->mp, 1, sizeof(DavResource));
    res->session = sn;
    
    // set name, path and href
    sstr_t n = sstr(name);
    res->name = sstrdup_a(sn->mp->allocator, n).ptr;
    if(n.length > 0 && n.ptr[n.length-1] == '/') {
        res->name[n.length-1] = '\0';
    }
    
    char *path = util_concat_path(parent_path, name); 
    res->path = dav_session_strdup(sn, path);
    
    res->href = href;
    
    // initialize resource data
    res->data = resource_data_new(sn);
    
    // cache href/path
    if(href) {
        dav_session_cache_path(sn, sstr(path), sstr(href));
    }
    free(path);
    
    return res;
}

void resource_free_properties(DavSession *sn, UcxMap *properties) {
    UcxMapIterator i = ucx_map_iterator(properties);
    char *property;
    UCX_MAP_FOREACH(key, property, i) {
        dav_session_free(sn, property);
    }
    ucx_map_free(properties);
}

void dav_resource_free(DavResource *res) {
    DavSession *sn = res->session;
    
    dav_session_free(sn, res->name);
    dav_session_free(sn, res->path);
    if(res->href) {
        dav_session_free(sn, res->href);
    }
    
    DavResourceData *data = res->data;
    resource_free_properties(sn, data->properties);
    
    UCX_FOREACH(elm, data->set) {
        DavProperty *p = elm->data;
        dav_session_free(sn, p->ns->name);
        if(p->ns->prefix) {
            dav_session_free(sn, p->ns->prefix);
        }
        dav_session_free(sn, p->ns);
        
        dav_session_free(sn, p->name);
        dav_session_free(sn, p->value);
        dav_session_free(sn, p);
    }
    
    UCX_FOREACH(elm, data->remove) {
        DavProperty *p = elm->data;
        dav_session_free(sn, p->ns->name);
        if(p->ns->prefix) {
            dav_session_free(sn, p->ns->prefix);
        }
        dav_session_free(sn, p->ns);
        
        dav_session_free(sn, p->name);
        dav_session_free(sn, p->value);
        dav_session_free(sn, p);
    }
    
    if(!data->read && data->content) {
        dav_session_free(sn, data->content);
    }
    dav_session_free(sn, data);
    
    dav_session_free(sn, res);
}

void dav_resource_free_all(DavResource *res) {
    DavResource *child = res->children;
    dav_resource_free(res);
    while(child) {
        DavResource *next = child->next;
        dav_resource_free_all(child);
        child = next;
    }
}

void resource_set_href(DavResource *res, sstr_t href) {
    res->href = sstrdup_a(res->session->mp->allocator, href).ptr;
}

void resource_set_info(DavResource *res, char *href_str) {
    char *url_str = NULL;
    curl_easy_getinfo(res->session->handle, CURLINFO_EFFECTIVE_URL, &url_str);
    sstr_t name = sstr(util_resource_name(href_str));
    sstr_t href = sstr(href_str);
    
    sstr_t base_href = sstr(util_url_path(res->session->base_url));
    sstr_t path = sstrsubs(href, base_href.length - 1);
    
    UcxAllocator *a = res->session->mp->allocator;
    CURL *handle = res->session->handle;
    
    int nlen = 0;
    char *uname = curl_easy_unescape(handle, name.ptr, name.length , &nlen);
    int plen = 0;
    char *upath = curl_easy_unescape(handle, path.ptr, path.length, &plen); 
    
    res->name = sstrdup_a(a, sstrn(uname, nlen)).ptr;
    res->href = sstrdup_a(a, href).ptr;
    res->path = sstrdup_a(a, sstrn(upath, plen)).ptr;
    
    curl_free(uname);
    curl_free(upath);
}

DavResourceData* resource_data_new(DavSession *sn) {
    DavResourceData *data = ucx_mempool_malloc(
            sn->mp,
            sizeof(DavResourceData));
    if(!data) {
        return NULL;
    }
    data->properties = ucx_map_new_a(sn->mp->allocator, 32);
    data->set = NULL;
    data->remove = NULL;
    data->content = NULL;
    data->read = NULL;
    data->length = 0;
    return data;
}

char* dav_resource_get_href(DavResource *resource) {
    if(!resource->href) {
        resource->href = dav_session_get_href(
                resource->session,
                resource->path);
    }
    return resource->href;
}

void resource_add_property(DavResource *res, char *ns, char *name, char *val) {
    if(!val) {
        return;
    }
    
    UcxKey key = dav_property_key(ns, name);
    sstr_t v = sstrdup_a(res->session->mp->allocator, sstr(val));
    ucx_map_put(((DavResourceData*)res->data)->properties, key, v.ptr);
    free(key.data);
}

char* resource_get_property(DavResource *res, char *ns, char *name) {
    UcxKey key = dav_property_key(ns, name);
    char *property = resource_get_property_k(res, key);
    free(key.data);
    return property;
}

char* resource_get_property_k(DavResource *res, UcxKey key) {
    DavResourceData *data = (DavResourceData*)res->data;
    return ucx_map_get(data->properties, key);
}

UcxKey dav_property_key(char *ns, char *name) {
    return dav_property_key_a(ucx_default_allocator(), ns, name);
}

UcxKey dav_property_key_a(UcxAllocator *a, char *ns, char *name) {
    sstr_t ns_str = sstr(ns);
    sstr_t name_str = sstr(name);
    
    sstr_t key;
    key = sstrcat_a(a, 4, ns_str, S("\0"), name_str, S("\0"));
    
    return ucx_key(key.ptr, key.length);
}


void resource_add_child(DavResource *parent, DavResource *child) {
    child->next = NULL;
    if(parent->children) {
        DavResource *last = parent->children;
        while(last->next) {
            last = last->next;
        }
        last->next = child;
        child->prev = last;
    } else {
        child->prev = NULL;
        parent->children = child;
    }
    child->parent = parent;
}

static int resource_cmp(DavResource *res1, DavResource *res2, DavOrderCriterion *cr) {
    if(!(res1 && res2)) {
        return 0;
    }
    
    int ret;
    if(cr->type == 0) {
        switch(cr->column.resprop) {
            case DAVQL_RES_NAME: {
                ret = strcmp(res1->name, res2->name);
                break;
            }
            case DAVQL_RES_PATH: {
                ret = strcmp(res1->path, res2->path);
                break;
            }
            case DAVQL_RES_HREF: {
                ret = strcmp(res1->href, res2->href);
                break;
            }
            case DAVQL_RES_CONTENTLENGTH: {
                int c = res1->contentlength == res2->contentlength;
                ret = c ? 0 : (res1->contentlength < res2->contentlength?-1:1);
                break;
            }
            case DAVQL_RES_CONTENTTYPE: {
                ret = strcmp(res1->contenttype, res2->contenttype);
                break;
            }
            case DAVQL_RES_CREATIONDATE: {
                int c = res1->creationdate == res2->creationdate;
                ret = c ? 0 : (res1->creationdate < res2->creationdate?-1:1);
                break;
            }
            case DAVQL_RES_LASTMODIFIED: {
                int c = res1->lastmodified == res2->lastmodified;
                ret = c ? 0 : (res1->lastmodified < res2->lastmodified?-1:1);
                break;
            }
            case DAVQL_RES_ISCOLLECTION: {
                int c = res1->iscollection == res2->iscollection;
                ret = c ? 0 : (res1->iscollection < res2->iscollection?-1:1);
                break;
            }
            default: ret = 0;
        }
    } else if(cr->type == 1) {
        char *value1 = resource_get_property_k(res1, cr->column.property);
        char *value2 = resource_get_property_k(res2, cr->column.property);
        if(!value1) {
            ret = value2 ? -1 : 0;
        } else if(!value2) {
            ret = value1 ? 1 : 0;
        } else {
            ret = strcmp(value1, value2);
        }
    } else {
        return 0;
    }
    
    return cr->descending ? -ret : ret;
}

void resource_add_ordered_child(DavResource *parent, DavResource *child, UcxList *ordercr) {
    if(!ordercr) {
        resource_add_child(parent, child);
        return;
    }
    
    child->parent = parent;
    
    if(!parent->children) {
        child->next = NULL;
        child->prev = NULL;
        parent->children = child;
    } else {
        DavResource *resource = parent->children;
        while(resource) {
            int r = 0;
            UCX_FOREACH(elm, ordercr) {
                DavOrderCriterion *cr = elm->data;
                r = resource_cmp(child, resource, cr);
                if(r != 0) {
                    break;
                }
            }
            
            if(r < 0) {
                // insert child before resource
                child->prev = resource->prev;
                child->next = resource;
                if(resource->prev) {
                    resource->prev->next = child;
                } else {
                    parent->children = child;
                }
                resource->prev = child;
                break;
            } if(!resource->next) {
                // append child
                child->prev = resource;
                child->next = NULL;
                resource->next = child;
                break;
            } else {
                resource = resource->next;
            }
        }
    }
}

char* dav_get_property(DavResource *res, char *name) {
    char *pns;
    char *pname;
    dav_get_property_namespace_str(res->session->context, name, &pns, &pname);
    return dav_get_property_ns(res, pns, pname);
}

char* dav_get_property_ns(DavResource *res, char *ns, char *name) {
    char *property = resource_get_property(res, ns, name);
    DavResourceData *data = res->data;
    // resource_get_property only returns persistent properties
    // check the remove and set list
    if(property) {
        // if the property is in the remove list, we return NULL
        UCX_FOREACH(elm, data->remove) {
            DavProperty *p = elm->data;
            if(!strcmp(p->name, name) && !strcmp(p->ns->name, ns)) {
                return NULL;
            }
        }
    }
    // the set list contains property updates
    // we return an updated property if possible
    UCX_FOREACH(elm, data->set) {
        DavProperty *p = elm->data;
        if(!strcmp(p->name, name) && !strcmp(p->ns->name, ns)) {
            return p->value;
        }
    }
    // no property update
    return property;
}

void dav_set_property(DavResource *res, char *name, char *value) {
    char *pns;
    char *pname;
    dav_get_property_namespace_str(res->session->context, name, &pns, &pname);
    dav_set_property_ns(res, pns, pname, value);
}

void dav_set_property_ns(DavResource *res, char *ns, char *name, char *value) {
    UcxAllocator *a = res->session->mp->allocator;
    DavResourceData *data = res->data;
    
    DavProperty *property = dav_session_malloc(
            res->session,
            sizeof(DavProperty));
    property->name = dav_session_strdup(res->session, name);
    property->value = dav_session_strdup(res->session, value);
    
    DavNamespace *namespace = dav_session_malloc(
            res->session,
            sizeof(DavNamespace));
    namespace->prefix = NULL;
    namespace->name = dav_session_strdup(res->session, ns);
    property->ns = namespace;
    
    data->set = ucx_list_append_a(a, data->set, property);
}

void dav_remove_property(DavResource *res, char *name) {
    char *pns;
    char *pname;
    dav_get_property_namespace_str(res->session->context, name, &pns, &pname);
    dav_remove_property_ns(res, pns, pname);
}

void dav_remove_property_ns(DavResource *res, char *ns, char *name) {
    DavResourceData *data = res->data;
    UcxAllocator *a = res->session->mp->allocator;
    
    DavProperty *property = dav_session_malloc(
            res->session,
            sizeof(DavProperty));
    property->name = sstrdup_a(a, sstr(name)).ptr;
    property->value = NULL;
    
    DavNamespace *namespace = dav_session_malloc(
            res->session,
            sizeof(DavNamespace));
    namespace->prefix = NULL;
    namespace->name = sstrdup_a(a, sstr(ns)).ptr;
    property->ns = namespace;
    
    data->remove = ucx_list_append_a(a, data->remove, property);
}

static int compare_propname(const void *a, const void *b) {
    const DavPropName *p1 = a;
    const DavPropName *p2 = b;
    
    int result = strcmp(p1->ns, p2->ns);
    if(result) {
        return result;
    } else {
        return strcmp(p1->name, p2->name);
    }
}

DavPropName* dav_get_property_names(DavResource *res, size_t *count) {
    DavResourceData *data = res->data;
    
    *count = data->properties->count;
    DavPropName *names = dav_session_calloc(
            res->session,
            *count,
            sizeof(DavPropName));
    
    
    UcxMapIterator i = ucx_map_iterator(data->properties);
    void *value;
    int j = 0;
    UCX_MAP_FOREACH(key, value, i) {
        DavPropName *name = &names[j];
        // the map key is namespace + '\0' + name
        name->ns = key.data;
        for(int k=0;j<key.len;k++) {
            if(((char*)key.data)[k] == '\0') {
                name->name = (char*)key.data + k + 1;
                break;
            }
        }
        j++;
    }
    
    qsort(names, *count, sizeof(DavPropName), compare_propname);
    
    return names;
}


void dav_set_content(DavResource *res, void *stream, dav_read_func read_func) {
    DavResourceData *data = res->data;
    data->content = stream;
    data->read = read_func;
    data->length = 0;
}

void dav_set_content_data(DavResource *res, char *content, size_t length) {
    DavSession *sn = res->session;
    DavResourceData *data = res->data;
    data->content = dav_session_malloc(sn, length);
    memcpy(data->content, content, length);
    data->read = NULL;
    data->length = length;
}


int dav_load(DavResource *res) {
    UcxBuffer *rqbuf = create_allprop_propfind_request();
    int ret = dav_propfind(res->session, res, rqbuf);
    ucx_buffer_free(rqbuf);
    return ret;
}

int dav_store(DavResource *res) {
    DavSession *sn = res->session;
    DavResourceData *data = res->data;
    
    util_set_url(sn, dav_resource_get_href(res));
      
    // store content
    if(data->content) {
        int encryption = DAV_ENCRYPT_CONTENT(sn) && sn->key;
        CURLcode ret;
        if(encryption) {
            AESEncrypter *enc = NULL;
            UcxBuffer *buf = NULL;
            if(data->read) {
                enc = aes_encrypter_new(sn->key, data->content, data->read);
            } else {
                buf = ucx_buffer_new(data->content, data->length, 0);
                buf->size = data->length;
                enc = aes_encrypter_new(
                        sn->key,
                        buf,
                        (dav_read_func)ucx_buffer_read);
            }
            
            // put resource
            ret = do_put_request(
                    sn->handle,
                    enc,
                    (dav_read_func)aes_read,
                    0);
            
            // get sha256 hash
            char sha[SHA256_DIGEST_LENGTH];
            dav_get_hash(&enc->sha256, sha);
            char *enc_hash = aes_encrypt(sha, SHA256_DIGEST_LENGTH, sn->key);
            
            aes_encrypter_close(enc);
            if(buf) {
                ucx_buffer_free(buf);
            }
            
            // add crypto properties
            // TODO: store the properties later
            if(resource_add_crypto_info(sn, res->href, res->name, enc_hash)) {
                free(enc_hash);
                return 1;
            }
            resource_add_property(res, DAV_NS, "crypto-hash", enc_hash);
            free(enc_hash);
        } else {
            ret = do_put_request(
                    sn->handle,
                    data->content,
                    data->read,
                    data->length);
        }
        
        int status = 0;
        curl_easy_getinfo(sn->handle, CURLINFO_RESPONSE_CODE, &status);
        if(ret == CURLE_OK && (status >= 200 && status < 300)) {
            res->session->error = 0;
            // cleanup node data
            if(!data->read) {
                ucx_mempool_free(sn->mp, data->content);
            }
            data->content = NULL;
            data->read = NULL;
            data->length = 0;
        } else {
            dav_session_set_error(sn, ret, status);
            return 1;
        }
    }
    
    // store properties
    if(data->set || data->remove) {
        UcxBuffer *request = create_proppatch_request(data);
        UcxBuffer *response = ucx_buffer_new(NULL, 1024, UCX_BUFFER_AUTOEXTEND);

        CURLcode ret = do_proppatch_request(sn->handle, request, response);
        int status = 0;
        curl_easy_getinfo (sn->handle, CURLINFO_RESPONSE_CODE, &status);
        if(ret == CURLE_OK && status == 207) {
            //printf("%s\n", response->space);
            // TODO: parse response
            // TODO: cleanup node data correctly
            data->set = NULL;
            data->remove = NULL;
        } else {
            dav_session_set_error(sn, ret, status);
            return 1;
        }
    }
    sn->error = DAV_OK;
    return 0;
}

int dav_get_content(DavResource *res, void *stream, dav_write_func write_fnc) { 
    DavSession *sn = res->session;
    CURL *handle = sn->handle;
    util_set_url(res->session, dav_resource_get_href(res));
    
    // check encryption
    AESDecrypter *dec = NULL;
    if(DAV_DECRYPT_CONTENT(sn)) {
        char *keyname = dav_get_property_ns(res, DAV_NS, "crypto-key");
        if(keyname) {
            DavKey *key = dav_context_get_key(sn->context, keyname);
            if(key) {
                dec = aes_decrypter_new(key, stream, write_fnc);
                stream = dec;
                write_fnc = (dav_write_func)aes_write;
            }
        }
    }
    
    curl_easy_setopt(handle, CURLOPT_HTTPHEADER, NULL);
    curl_easy_setopt(handle, CURLOPT_CUSTOMREQUEST, NULL);
    curl_easy_setopt(handle, CURLOPT_PUT, 0L);
    curl_easy_setopt(handle, CURLOPT_UPLOAD, 0L);
    
    curl_easy_setopt(handle, CURLOPT_WRITEFUNCTION, write_fnc);
    curl_easy_setopt(handle, CURLOPT_WRITEDATA, stream);
    
    CURLcode ret = curl_easy_perform(handle);
    
    char *hash = NULL;
    if(dec) {
        // get hash
        char sha[SHA256_DIGEST_LENGTH];
        dav_get_hash(&dec->sha256, sha);
        hash = util_hexstr(sha, 32);
        
        aes_decrypter_close(dec);
    }
    
    int status = 0;
    curl_easy_getinfo (handle, CURLINFO_RESPONSE_CODE, &status);
    if(ret == CURLE_OK && (status >= 200 && status < 300)) {
        int verify_failed = 0;
        if(DAV_DECRYPT_CONTENT(sn)) {
            // try to verify the content
            char *res_hash = dav_get_property_ns(res, DAV_NS, "crypto-hash");

            if(res_hash) {
                size_t len = 0;
                char *dec_hash = aes_decrypt(res_hash, &len, sn->key);
                char *hex_hash = util_hexstr(dec_hash, 32);
                if(strcmp(hash, hex_hash)) {
                    verify_failed = 1;
                }
                free(dec_hash);
                free(hex_hash);
            }
        }
        
        if(verify_failed) {
            res->session->error = DAV_CONTENT_VERIFICATION_ERROR;
            return 1;
        }
        
        res->session->error = DAV_OK;
        return 0;
    } else {
        dav_session_set_error(res->session, ret, status);
        return 1;
    }
}

DavResource* dav_create_child(DavResource *parent, char *name) {
    DavResource *res = dav_resource_new_child(parent->session, parent, name);
    if(dav_create(res)) {
        // TODO: free resource
        return NULL;
    } else {
        return res;
    }
}

int dav_delete(DavResource *res) {
    CURL *handle = res->session->handle;
    util_set_url(res->session, dav_resource_get_href(res));
    
    UcxBuffer *response = ucx_buffer_new(NULL, 4096, UCX_BUFFER_AUTOEXTEND);
    CURLcode ret = do_delete_request(handle, response);
    int status = 0;
    curl_easy_getinfo (handle, CURLINFO_RESPONSE_CODE, &status);
    if(ret == CURLE_OK && (status >= 200 && status < 300)) {
        res->session->error = DAV_OK;
        
        // TODO: parse response
        // TODO: free res
        
        return 0;
    } else {
        dav_session_set_error(res->session, ret, status);
        return 1;
    }
}

static int create_ancestors(DavSession *sn, char *href, char *path) {
    CURL *handle = sn->handle;
    CURLcode code;
    int status = 0;
    int ret = 0;
    
    if(strlen(path) <= 1) {
        return 0;
    }
    
    char *p = util_parent_path(path);
    char *h = util_parent_path(href);
    
    for(int i=0;i<2;i++) {
        util_set_url(sn, h);
        code = do_mkcol_request(handle);
        curl_easy_getinfo(handle, CURLINFO_RESPONSE_CODE, &status);
        if(status == 201) {
            // resource successfully created
            char *name = util_resource_name(p);
            int len = strlen(name);
            if(name[len - 1] == '/') {
                name[len - 1] = '\0';
            }
            if(resource_add_crypto_info(sn, h, name, NULL)) {
                // TODO: error
            }
            break;
        } else if(status == 405) {
            // parent already exists
            break;
        } else if(status == 409) {
            // parent doesn't exist
            if(create_ancestors(sn, h, p)) {
                ret = 1;
                break;
            }
        } else {
            dav_session_set_error(sn, code, status);
            ret = 1;
            break;
        }
    }
    
    free(p);
    free(h);
    return ret;
}

static int create_resource(DavResource *res, int *status) {
    DavSession *sn = res->session;
    CURL *handle = sn->handle;
    util_set_url(sn, dav_resource_get_href(res));
    
    CURLcode code;
    if(res->iscollection) {
        code = do_mkcol_request(handle);
    } else {
        code = do_put_request(handle, "", NULL, 0); 
    }
    int s = 0;
    curl_easy_getinfo(handle, CURLINFO_RESPONSE_CODE, &s);
    *status = s;
    if(code == CURLE_OK && (s >= 200 && s < 300)) {
        sn->error = DAV_OK;
        // if the session has encrypted file names, add crypto infos
        resource_add_crypto_info(sn, res->href, res->name, NULL); // TODO: check return type
        
        // do a minimal propfind request
        UcxBuffer *rqbuf = create_propfind_request(sn, NULL);
        int ret = dav_propfind(sn, res, rqbuf);
        ucx_buffer_free(rqbuf);
        return ret;
    } else {
        dav_session_set_error(sn, code, s);
        return 1;
    }
}

int dav_create(DavResource *res) {
    int status;
    if(!create_resource(res, &status)) {
        // resource successfully created
        return 0;
    }
    
    if(status == 403 || status == 409) {
        // create intermediate collections
        if(create_ancestors(res->session, res->href, res->path)) {
            return 1;
        }
    }
    
    return create_resource(res, &status);
}

int dav_exists(DavResource *res) {
    DavSession *sn = res->session;
    CURL *handle = sn->handle;
    util_set_url(sn, dav_resource_get_href(res));
    
    CURLcode ret = do_head_request(handle);
    int status = 0;
    curl_easy_getinfo (handle, CURLINFO_RESPONSE_CODE, &status);
    if(ret == CURLE_OK && (status >= 200 && status < 300)) {
        return 1;
    } else {
        dav_session_set_error(sn, ret, status);
        return 0;
    }
}


int resource_add_crypto_info(DavSession *sn, char *href, char *name, char *hash) {
    if(!DAV_IS_ENCRYPTED(sn)) {
        return 0;
    }
    
    UcxBuffer *request = create_crypto_proppatch_request(sn, sn->key, name, hash);
    UcxBuffer *response = ucx_buffer_new(NULL, 1024, UCX_BUFFER_AUTOEXTEND);
    
    util_set_url(sn, href);
    CURLcode ret = do_proppatch_request(sn->handle, request, response);
    ucx_buffer_free(request);
    int status = 0;
    curl_easy_getinfo (sn->handle, CURLINFO_RESPONSE_CODE, &status);
    if(ret == CURLE_OK && status == 207) {
        // TODO: parse response
        sn->error = DAV_OK;   
        ucx_buffer_free(response);
        return 0;
    } else {
        dav_session_set_error(sn, ret, status);
        ucx_buffer_free(response);
        return 1;
    }
}