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online_db.ml
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online_db.ml
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(*
Copyright (c) 2008-2009 The Regents of the University of California
Copyright (c) 2010 Luca de Alfaro
All rights reserved.
Authors: Luca de Alfaro, Ian Pye, B. Thomas Adler
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.
3. The names of the contributors may not be used to endorse or promote
products derived from this software without specific prior written
permission.
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 OWNER 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.
*)
open Online_types
open Mysql
open Sexplib.Conv
open Sexplib.Sexp
open Sexplib
open Online_log
TYPE_CONV_PATH "UCSC_WIKI_RESEARCH"
(* Returned whenever something is not found *)
exception DB_Not_Found
(* Internal error *)
exception DB_Internal_Error
(* Commit failed, or other database error that may have to cause a rollback. *)
exception DB_TXN_Bad
(* ExecAPI failed *)
exception DB_Exec_Error
(* Read/write colored revisions from wrong blob ids. *)
exception DB_Illegal_blob_id
(* This is the function that sexplib uses to convert floats *)
Sexplib.Conv.default_string_of_float := (fun n -> Printf.sprintf "%.3f" n);;
(* Represents the revision table in memory *)
type revision_t = {
rev_id: int;
rev_page: int;
rev_text_id: int;
rev_timestamp: string;
rev_user: int;
rev_user_text: string;
rev_is_minor: bool;
}
(* Proper chronological ordering for revision_t *)
let revision_t_asc_cron (r1: revision_t) (r2: revision_t) : int =
compare (r1.rev_timestamp, r1.rev_id) (r2.rev_timestamp, r2.rev_id)
let revision_t_desc_cron x y = - revision_t_asc_cron x y
(* When we read the revisions from disk, we ask for them to be sorted
in order of timestamp, but what we really need is a (timestamp,
rev_id) order. Thus, we ask for extra revisions, to compensate for the
fact that there can be multiple revisions with the same timestamp.
If we wish to have n revisions, we will ask the db for
n * num_max_same_timestamp + num_extra_revisions revisions, so that
even if the db query is sorted by timestamp, we will be able to have
a long enough final answer. *)
let num_max_same_timestamp = 2
let num_extra_revisions = 5
let set_is_minor ism = match ism with
| 0 -> false
| 1 -> true
| _ -> assert false
(* Given a row, return a new online revision *)
let rev_row2revision_t row =
{
rev_id = (not_null int2ml row.(0)); (* rev id *)
rev_page = (not_null int2ml row.(1)); (* page id *)
rev_text_id = (not_null int2ml row.(2)); (* text id *)
rev_timestamp = (not_null str2ml row.(3)); (* timestamp *)
rev_user = (not_null int2ml row.(4)); (* user id *)
rev_user_text = (not_null str2ml row.(5)); (* user name *)
rev_is_minor = (set_is_minor (not_null int2ml row.(6))); (* is_minor *)
}
(* This is the type of a vote data *)
type vote_t = {
vote_time: string;
vote_page_id: int;
vote_revision_id: int;
vote_voter_name: string;
}
(* This is the type of a set of signatures, as visible from outside. *)
type page_sig_t = page_sig_disk_t
let empty_page_sigs = []
(* Produces the key for storing a blob in the database *)
let make_blob_key (page_id: int) (blob_id: int) : string =
Printf.sprintf "%012d%012d" page_id blob_id
(** [get_cmd_output cmdline] returns the output from an external command.
An exception is thrown if there is a problem. *)
let get_cmd_output (cmdline: string) : string =
let cmdout = Unix.open_process_in cmdline in
let bufSize = 8192 in
let buf = String.create bufSize in
let completeFile = Buffer.create bufSize in
let rec loop () =
let chunkLen = input cmdout buf 0 bufSize in
if (chunkLen > 0) then begin
let actualChunk = String.sub buf 0 chunkLen in
Buffer.add_string completeFile actualChunk;
loop ()
end else
raise End_of_file
in begin
try
loop ()
with End_of_file -> begin
let status = Unix.close_process_in cmdout in
match status with
| Unix.WEXITED 0 -> Buffer.contents completeFile
| _ -> raise DB_Exec_Error
end
end
(** This class provides a handle for accessing the database in the on-line
implementation. *)
class db
(db_prefix : string)
(mediawiki_dbh : Mysql.dbd)
(global_dbh : Mysql.dbd option)
(db_name: string)
(rev_base_path: string option)
(colored_base_path: string option)
(debug_mode : bool)
(keep_text_cache : bool) =
object(self)
method private db_exec dbh s =
if debug_mode then !online_logger#log (s ^ "\n");
begin
try
Mysql.exec dbh s
with Mysql.Error e ->
!online_logger#log e;
raise DB_TXN_Bad
end
(* ================================================================ *)
(* General methods *)
method get_base_path : string option = colored_base_path
(* ================================================================ *)
(* Disconnect *)
method close : unit =
Mysql.disconnect mediawiki_dbh;
match global_dbh with
| Some dbh -> Mysql.disconnect dbh
| None -> ()
(* ================================================================ *)
(* Locks and commits. *)
(** [get_page_lock page_id timeout] gets a lock for page [page_id],
to guarantee mutual exclusion on the updates for page [page_id].
The lock is waited for at most time [timeout] seconds. The
function returns [true] if the lock was acquired. *)
method get_page_lock (page_id: int) (timeout: int) : bool =
let lock_name = Printf.sprintf "%s.%swikitrust_page.%d" db_name db_prefix page_id in
let s = Printf.sprintf "SELECT GET_LOCK(%s,%s)" (ml2str lock_name) (ml2int timeout) in
match fetch (self#db_exec mediawiki_dbh s) with
None -> raise DB_Internal_Error
| Some row -> ((not_null int2ml row.(0)) = 1)
(** [is_page_lock_free page_id] checks whether the lock for page
[page_id] is available (there is no guarantee that somebody does
not lock the page between this test and a subsequent call to
[get_page_lock]. *)
method is_page_lock_free (page_id: int) : bool =
let lock_name = Printf.sprintf "%s.%swikitrust_page.%d" db_name db_prefix page_id in
let s = Printf.sprintf "SELECT IS_FREE_LOCK(%s)" (ml2str lock_name) in
match fetch (self#db_exec mediawiki_dbh s) with
None -> raise DB_Internal_Error
| Some row -> ((not_null int2ml row.(0)) = 1)
(** [release_page_lock page_id] releases the lock for page
[page_id], to guarantee mutual exclusion on the updates for page
[page_id]. *)
method release_page_lock (page_id: int) : unit =
let lock_name = Printf.sprintf "%s.%swikitrust_page.%d" db_name db_prefix page_id in
let s = Printf.sprintf "SELECT RELEASE_LOCK(%s)" (ml2str lock_name) in
ignore (self#db_exec mediawiki_dbh s)
(** Start a transaction. *)
method start_transaction : unit =
ignore (self#db_exec mediawiki_dbh "START TRANSACTION")
(** rollback a transaction. *)
method rollback_transaction : unit =
!online_logger#log "ROLLBACK\n";
ignore (self#db_exec mediawiki_dbh "ROLLBACK")
(* Commits any changes to the db *)
method commit : unit =
ignore (self#db_exec mediawiki_dbh "COMMIT");
begin
match Mysql.status mediawiki_dbh with
| StatusError err ->
begin
!online_logger#log "COMMIT error encountered\n";
raise DB_TXN_Bad
end
| _ -> ()
end
(* ================================================================ *)
(* Global methods. *)
(** [get_histogram] Returns a histogram showing the number of users
at each reputation level, and the median. *)
method get_histogram : float array * float =
let s = Printf.sprintf "SELECT median, rep_0, rep_1, rep_2, rep_3, rep_4, rep_5, rep_6, rep_7, rep_8, rep_9 FROM %swikitrust_global" db_prefix in
match fetch (self#db_exec mediawiki_dbh s) with
None -> begin
(* No histogram is found. It creates a default one, and returns it. *)
let s = Printf.sprintf "INSERT INTO %swikitrust_global VALUES (0,0,0,0,0,0,0,0,0,0,0)" db_prefix in
ignore (self#db_exec mediawiki_dbh s);
([|0.; 0.; 0.; 0.; 0.; 0.; 0.; 0.; 0.; 0.|], 0.)
end
| Some row -> ([| not_null float2ml row.(1); not_null float2ml row.(2); not_null float2ml row.(3);
not_null float2ml row.(4); not_null float2ml row.(5);
not_null float2ml row.(6); not_null float2ml row.(7);
not_null float2ml row.(8); not_null float2ml row.(9); not_null float2ml row.(10);
|], (not_null float2ml row.(0)))
(** write_histogram delta_hist median] increments the db histogram
of user reputations according to the array [delta_hist], and
writes that the new median is [median]. *)
method write_histogram (delta_hist : float array) (median: float) : unit =
let s = Printf.sprintf "UPDATE %swikitrust_global SET median = %s, rep_0 = rep_0 + %s, rep_1 = rep_1 + %s, rep_2 = rep_2 + %s, rep_3 = rep_3 + %s, rep_4 = rep_4 + %s, rep_5 = rep_5 + %s, rep_6 = rep_6 + %s, rep_7 = rep_7 + %s, rep_8 = rep_8 + %s, rep_9 = rep_9 + %s"
db_prefix
(ml2float median)
(ml2float delta_hist.(0)) (ml2float delta_hist.(1)) (ml2float delta_hist.(2)) (ml2float delta_hist.(3))
(ml2float delta_hist.(4)) (ml2float delta_hist.(5)) (ml2float delta_hist.(6)) (ml2float delta_hist.(7))
(ml2float delta_hist.(8)) (ml2float delta_hist.(9)) in
ignore (self#db_exec mediawiki_dbh s)
(** set_histogram hist median] sets the histogram and the median in the
database. *)
method set_histogram (hist : float array) (median: float) : unit =
(* Ensures that there is only one row. *)
let s = Printf.sprintf "DELETE FROM %swikitrust_global" db_prefix in
ignore (self#db_exec mediawiki_dbh s);
(* Inserts the new histogram. *)
let s = Printf.sprintf "REPLACE INTO %swikitrust_global (rep_0, rep_1, rep_2, rep_3, rep_4, rep_5, rep_6, rep_7, rep_8, rep_9, median) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s)"
db_prefix
(ml2float hist.(0)) (ml2float hist.(1)) (ml2float hist.(2))
(ml2float hist.(3)) (ml2float hist.(4)) (ml2float hist.(5))
(ml2float hist.(6)) (ml2float hist.(7)) (ml2float hist.(8))
(ml2float hist.(9)) (ml2float median)
in
ignore (self#db_exec mediawiki_dbh s)
(** [fetch_last_colored_rev_time req_page_id] returns the timestamp and the
revision id of the most recent revision that has been colored.
If [req_page_id] specifies a page, then only that page is considered.
Raises DB_Not_Found if no revisions have been colored. *)
method fetch_last_colored_rev_time (req_page_id: int option) : (string * int) =
let wr = match req_page_id with
None -> ""
| Some p_id -> Printf.sprintf "WHERE page_id = %s" (ml2int p_id)
in
(* gets some extra revisions to account for possible
timestamp collisions. *)
let s = Printf.sprintf "SELECT revision_id, page_id, text_id, time_string, user_id, username, is_minor FROM %swikitrust_revision %s ORDER BY time_string DESC LIMIT %s" db_prefix wr (ml2int num_extra_revisions) in
let rev_list = Mysql.map
(self#db_exec mediawiki_dbh s) rev_row2revision_t in
(* Sorts the list in descending order *)
let sorted_rev_list = List.sort revision_t_desc_cron rev_list in
if (List.length sorted_rev_list) = 0
then raise DB_Not_Found
else begin
let r = List.hd sorted_rev_list in
(r.rev_timestamp, r.rev_id)
end
(** [fetch_all_revs_after req_page_id req_rev_id timestamp rev_id
limit] returns all revs created after the given [timestamp], or
at the same [timestamp], with revision id at least [rev_id], up
to the maximim number [limit]. If [req_page_id] specifies a
page, then only that page is considered. If [req_rev_id]
specifies a revision, then that revision is included in the
result. *)
method fetch_all_revs_after
(req_page_id: int option)
(req_rev_id: int option)
(timestamp : string)
(rev_id : int)
(max_revs_to_return : int)
: revision_t list =
let wr = match req_page_id with
| None -> ""
| Some p_id -> Printf.sprintf "AND rev_page = %s" (ml2int p_id)
in
let rr = match req_rev_id with
| None -> ""
| Some r_id -> Printf.sprintf "rev_id = %s OR" (ml2int r_id)
in
let n_revs_to_request = max_revs_to_return * num_max_same_timestamp +
num_extra_revisions in
let s = Printf. sprintf "SELECT rev_id, rev_page, rev_text_id, rev_timestamp, rev_user, rev_user_text, rev_minor_edit FROM %srevision WHERE %s rev_timestamp >= %s %s ORDER BY rev_timestamp ASC LIMIT %s"
db_prefix
rr (ml2str timestamp) wr (ml2int n_revs_to_request) in
let rev_list = Mysql.map
(self#db_exec mediawiki_dbh s) rev_row2revision_t in
(* Sorts the list *)
let sorted_rev_list = List.sort revision_t_asc_cron rev_list in
(* Now we must go over the list, and:
* Discard any element that is smaller than or equal to
(timestamp, rev_id).
* Keep only max_revs_to_return revisions. *)
(* This function is folded on sorted_rev_list to compute the answer. *)
let f (res_l, k) el =
if k = 0
then (res_l, k)
else begin
if (el.rev_timestamp, el.rev_id) <= (timestamp, rev_id)
then (res_l, k)
else (res_l @ [el], k - 1)
end
in let (truncated_list, _) =
List.fold_left f ([], max_revs_to_return) sorted_rev_list in
truncated_list
(** [fetch_all_revs req_page_id max_revs_to_return] returns a list
of revisions in the database, in ascending order of timestamp,
of length at most [max_revs_to_return]. If [req_page_id]
specifies a page, then only that page is considered. *)
method fetch_all_revs (req_page_id: int option) (max_revs_to_return: int) : revision_t list =
let wr = match req_page_id with
None -> ""
| Some p_id -> Printf.sprintf "WHERE rev_page = %s" (ml2int p_id)
in
let n_revs_to_request = max_revs_to_return * num_max_same_timestamp +
num_extra_revisions in
let s = Printf.sprintf "SELECT rev_id, rev_page, rev_text_id, rev_timestamp, rev_user, rev_user_text, rev_minor_edit FROM %srevision %s ORDER BY rev_timestamp ASC LIMIT %s"
db_prefix wr (ml2int n_revs_to_request) in
let rev_list = Mysql.map
(self#db_exec mediawiki_dbh s) rev_row2revision_t in
(* Sorts the list *)
let sorted_rev_list = List.sort revision_t_asc_cron rev_list in
(* Now we must go over the list, and:
* Keep only max_revs_to_return revisions. *)
(* This function is folded on sorted_rev_list to compute the answer. *)
let f (res_l, k) el =
if k = 0
then (res_l, k)
else (res_l @ [el], k - 1)
in let (truncated_list, _) =
List.fold_left f ([], max_revs_to_return) sorted_rev_list in
truncated_list
(** [fetch_unprocessed_votes req_page_id n_events] returns at most
[n_events] unprocessed votes, starting from the oldest
unprocessed vote. If [req_page_id] specifies a page, then only
that page is considered. *)
method fetch_unprocessed_votes (req_page_id: int option) (n_events: int) : vote_t list =
let wr = match req_page_id with
None -> ""
| Some p_id -> Printf.sprintf "page_id = %s AND" (ml2int p_id)
in
let s = Printf.sprintf "SELECT voted_on, page_id, revision_id, voter_name FROM %swikitrust_vote WHERE %s NOT processed ORDER BY voted_on ASC LIMIT %s" db_prefix wr (ml2int n_events) in
let vote_row2vote_t row =
{
vote_time = (not_null str2ml row.(0));
vote_page_id = (not_null int2ml row.(1));
vote_revision_id = (not_null int2ml row.(2));
vote_voter_name = (not_null str2ml row.(3));
}
in
Mysql.map (self#db_exec mediawiki_dbh s) vote_row2vote_t
(** [mark_vote_as_processed (revision_id: int) (voter_name :
string)] marks a vote as processed. *)
method mark_vote_as_processed (revision_id: int) (voter_name : string)
: unit =
let s = Printf.sprintf "UPDATE %swikitrust_vote SET processed = TRUE WHERE revision_id = %s AND voter_name = %s"
db_prefix (ml2int revision_id) (ml2str voter_name) in
ignore (self#db_exec mediawiki_dbh s)
(* ================================================================ *)
(* Blob methods. *)
(** [read_blob page_id blob_id] reads the blob for page_id and blob_id,
either from the database, or from the filesystem, and returns it. *)
method read_blob (page_id: int) (blob_id: int)
: string option =
match colored_base_path with
None -> begin
(* The blobs are stored in the db. *)
let key_str = make_blob_key page_id blob_id in
let s = Printf.sprintf "SELECT blob_content from %swikitrust_blob WHERE blob_id = %s" db_prefix (ml2decimal key_str) in
let result = self#db_exec mediawiki_dbh s in
match Mysql.fetch result with
None -> None
| Some x -> Some (Revision_store.uncompress (not_null blob2ml x.(0)))
end
| Some b -> Revision_store.read_blob b page_id blob_id
(** [write_blob page_id blob_id blob_content] writes the blob [blob_content]
for [page_id], [blob_id] to either the filesystem or the database. *)
method write_blob
(page_id: int) (blob_id: int) (blob_content: string) : unit =
match colored_base_path with
None -> begin
(* The blobs are stored in the db. *)
let key_str = make_blob_key page_id blob_id in
let compressed_blob = Revision_store.compress blob_content in
let blob_db = ml2blob compressed_blob in
let s = Printf.sprintf "DELETE FROM %swikitrust_blob WHERE blob_id = %s"
db_prefix (ml2decimal key_str) in
ignore (self#db_exec mediawiki_dbh s);
let s = Printf.sprintf "INSERT INTO %swikitrust_blob (blob_id, blob_content) VALUES (%s, %s)" db_prefix (ml2decimal key_str) blob_db in
ignore (self#db_exec mediawiki_dbh s)
end
| Some b -> Revision_store.write_blob b page_id blob_id blob_content
(* ================================================================ *)
(* Page methods. *)
(* Methods for wikitrust_page *)
(** [init_page page_id] initializes the page information for
page [page_id]. *)
method init_page (page_id : int) (page_title : string option) : unit =
let info_string = ml2str
(string_of__of__sexp_of sexp_of_page_info_t
Online_types.page_info_default) in
let s = Printf.sprintf "INSERT INTO %swikitrust_page (page_id, page_info, page_title, last_blob) VALUES (%s, %s, %s, %s) ON DUPLICATE KEY UPDATE last_blob = last_blob, page_title = %s, page_info = %s"
db_prefix (ml2int page_id) info_string (match page_title with
| Some pt -> ml2str pt
| None -> "null")
(ml2int blob_locations.initial_location)
(match page_title with
| Some pt -> ml2str pt
| None -> "null")
info_string
in
ignore (self#db_exec mediawiki_dbh s)
(** [write_page_info page_id p_info] writes that the page [page_id]
has associated information [p_info]. The list of deleted chunks
of the page is not modified. *)
method write_page_info (page_id : int) (p_info: page_info_t) : unit =
let info_string = ml2str
(string_of__of__sexp_of sexp_of_page_info_t p_info) in
let s = Printf.sprintf "UPDATE %swikitrust_page SET page_info = %s WHERE page_id = %s"
db_prefix info_string (ml2int page_id) in
ignore (self#db_exec mediawiki_dbh s)
(** [read_page_info page_id] returns the page information for [page_id],
consisting of the page information proper and the open_page_blob_id. *)
method read_page_info (page_id : int) : page_info_t * int =
let s = Printf.sprintf "SELECT page_info, last_blob FROM %swikitrust_page WHERE page_id = %s" db_prefix (ml2int page_id) in
let result = self#db_exec mediawiki_dbh s in
match Mysql.fetch result with
None -> raise DB_Not_Found
| Some x ->
(of_string__of__of_sexp page_info_t_of_sexp (not_null str2ml x.(0)),
not_null int2ml x.(1))
(** [fetch_col_revs page_id timestamp rev_id fetch_limit] returns a
cursor that points to at most [fetch_limit] revisions of page
[page_id] with time prior or equal to [timestamp]. The ordering
goes backward in time. This function is used to read the
colored revisions that precede a given one. *)
method fetch_col_revs (page_id : int) (time_string: string) (rev_id: int) (fetch_limit: int): revision_t list =
let n_revs_to_get = fetch_limit * num_max_same_timestamp +
num_extra_revisions in
let s = Printf.sprintf "SELECT revision_id, page_id, text_id, time_string, user_id, username, is_minor FROM %swikitrust_revision WHERE page_id = %s AND time_string <= %s ORDER BY time_string DESC LIMIT %s" db_prefix (ml2int page_id) (ml2str time_string) (ml2int n_revs_to_get) in
let rev_list = Mysql.map
(self#db_exec mediawiki_dbh s) rev_row2revision_t in
(* Sorts the list in descending order *)
let sorted_rev_list = List.sort revision_t_desc_cron rev_list in
(* Now we must go over the list, and:
* Discard any element that is greater than or equal to
(timestamp, rev_id).
* Keep only fetch_limit revisions. *)
(* This function is folded on sorted_rev_list to compute the answer. *)
let f (res_l, k) el =
if k = 0
then (res_l, k)
else begin
if (el.rev_timestamp, el.rev_id) >= (time_string, rev_id)
then (res_l, k)
else (res_l @ [el], k - 1)
end
in let (truncated_list, _) =
List.fold_left f ([], fetch_limit) sorted_rev_list in
truncated_list
(** [get_mwpage_title page_id]
Returns the (list) of titles associated with page_id
in the MediaWiki tables *)
method get_mwpage_title (page_id : int) : string list =
let getstr row = (not_null str2ml row.(0)) in
let s = Printf.sprintf "SELECT page_title FROM %spage WHERE page_id = %s"
db_prefix (ml2int page_id) in
Mysql.map (self#db_exec mediawiki_dbh s) getstr
(** [get_mwpage_id page_title]
Returns the (list) of page_ids associated with page_title
in the MediaWiki tables *)
method get_mwpage_id (page_title : string) : int list =
let getint row = (not_null int2ml row.(0)) in
let s = Printf.sprintf "SELECT page_id FROM %spage WHERE page_title = %s"
db_prefix (ml2str page_title) in
Mysql.map (self#db_exec mediawiki_dbh s) getint
(** [delete_page page_id] deletes all the information related to page_id
in the system. With an option, we can specify whether to delete also
the information in the regular Mediawiki tables. *)
method delete_page (page_id: int) = begin
(* First, deletes the information in the db. *)
let s = Printf.sprintf
"DELETE FROM %swikitrust_revision WHERE page_id = %s"
db_prefix (ml2int page_id) in
ignore(self#db_exec mediawiki_dbh s);
let s = Printf.sprintf
"DELETE FROM %swikitrust_page WHERE page_id = %s"
db_prefix (ml2int page_id) in
ignore(self#db_exec mediawiki_dbh s);
(* in mediawiki API mode, we also control mediawiki tables... *)
let s = Printf.sprintf
"DELETE FROM %spage WHERE page_id = %s"
db_prefix (ml2int page_id) in
ignore(self#db_exec mediawiki_dbh s);
(* Deletes the cached revisions for the page; we only call
'delete_page' on error, so we really want to delete
the text cache as well. *)
self#erase_cached_rev_text page_id true;
(* Then, deletes the information, if any, in the blob pages *)
begin
match colored_base_path with
None -> begin
(* The blobs are stored in the db. *)
(* TODO: this is a hack! It would be much better to
store also the page_id in the wikitrust_blob table! *)
let p0 = make_blob_key page_id 0 in
let p1 = make_blob_key (page_id + 1) 0 in
let s = Printf.sprintf
"DELETE FROM %swikitrust_blob WHERE blob_id >= %s and blob_id < %s"
db_prefix (ml2decimal p0) (ml2decimal p1) in
ignore(self#db_exec mediawiki_dbh s)
end
| Some b -> begin
(* The blobs are stored in the filesystem. *)
ignore(Revision_store.delete_all_page_blobs b page_id)
end
end
end
(* Chunk methods *)
(** [write_page_chunks page_id chunk_list] writes that the page
with id [page_id] is associated with the "dead" strings of text
[chunk1], [chunk2], ..., where [chunk_list = [chunk1, chunk2,
...] ]. The chunk_list contains text that used to be present in
the article, but has been deleted. *)
method write_page_chunks (page_id : int) (c_list : chunk_t list) : unit =
let chunks_string =
(string_of__of__sexp_of (sexp_of_list sexp_of_chunk_t) c_list) in
self#write_blob page_id blob_locations.chunks_location chunks_string
(** [read_page_chunks page_id] returns the chunk list for page [page_id].
If the chunks cannot be found, returns the empty list: this happens
for new pages. *)
method read_page_chunks (page_id: int) : chunk_t list =
let chunks_string = self#read_blob page_id blob_locations.chunks_location in
match chunks_string with
None -> []
| Some s -> of_string__of__of_sexp (list_of_sexp chunk_t_of_sexp) s
(** [write_open_blob_id page_id blob_id] writes on the wikitrust_page table that
the open blob for [page_id] is [blob_id]. *)
method write_open_blob_id (page_id: int) (blob_id: int) : unit =
assert (blob_id >= blob_locations.initial_location);
let s = Printf.sprintf "UPDATE %swikitrust_page SET last_blob = %s WHERE page_id = %s" db_prefix (ml2int blob_id) (ml2int page_id) in
ignore (self#db_exec mediawiki_dbh s)
(* Signature methods *)
(** [read_page_sigs page_id] reads and returns the sigs for page
[page_id]. *)
method read_page_sigs (page_id: int) : page_sig_t =
let s = self#read_blob page_id blob_locations.sig_location in
match s with
None -> []
| Some s' -> (of_string__of__of_sexp page_sig_disk_t_of_sexp s')
(** [write_page_sigs page_id sigs] writes that the sigs
page [page_id] are [sigs]. *)
method write_page_sigs (page_id: int) (sigs: page_sig_t) : unit =
(* Creates a single string for the sigs. *)
let sig_string = string_of__of__sexp_of sexp_of_page_sig_disk_t sigs in
self#write_blob page_id blob_locations.sig_location sig_string
(** [list_pages_in_sigs page_sigs] returns the list of page ids in the page sigs. *)
method list_pages_in_sigs (sigs: page_sig_t) : int list =
let (l, _) = List.split sigs in l
(* Methods on the standard tables *)
(** [get_latest_rev_id_from_id page_id] returns the revision id of the most
recent revision of page [page_id], be the revision colored or not. *)
method get_latest_rev_id_of_page (page_id: int) : int =
let s = Printf.sprintf "SELECT max(A) FROM (SELECT max(revision_id) AS A FROM %swikitrust_revision WHERE page_id = %s UNION SELECT max(rev_id) AS A FROM %srevision WHERE rev_page = %s) AS t1;"
db_prefix (ml2int page_id) db_prefix (ml2int page_id) in
match fetch (self#db_exec mediawiki_dbh s) with
None -> raise DB_Not_Found
| Some x -> (match x.(0) with
| None -> raise DB_Not_Found
| Some maxr -> int2ml maxr)
(* ================================================================ *)
(* Revision methods. *)
(** [read_wikitrust_revision rev_id] reads a revision from the
wikitrust_revision table, returning the revision information,
the quality information, and the optional blob id. *)
method read_wikitrust_revision (revision_id: int)
: (revision_t * qual_info_t * int option) =
let s = Printf.sprintf "SELECT revision_id, page_id, text_id, time_string, user_id, username, is_minor, quality_info, blob_id FROM %swikitrust_revision WHERE revision_id = %s" db_prefix (ml2int revision_id) in
let result = self#db_exec mediawiki_dbh s in
match fetch result with
None -> raise DB_Not_Found
| Some x -> begin
let r = {
rev_id = not_null int2ml x.(0);
rev_page = not_null int2ml x.(1);
rev_text_id = not_null int2ml x.(2);
rev_timestamp = not_null str2ml x.(3);
rev_user = not_null int2ml x.(4);
rev_user_text = not_null str2ml x.(5);
rev_is_minor = set_is_minor (not_null int2ml x.(6));
} in
let q = of_string__of__of_sexp qual_info_t_of_sexp
(not_null str2ml x.(7)) in
let bid = not_null int2ml x.(8) in
let bid_opt =
if bid = blob_locations.invalid_location
then None
else Some bid
in (r, q, bid_opt)
end
(** [write_wikitrust_revision revision_info quality_info]
writes the wikitrust data associated with a revision. *)
method write_wikitrust_revision
(revision_info: revision_t)
(quality_info: qual_info_t)
(blob_id_opt: int option) : unit =
(* Blob id *)
let blob_id = match blob_id_opt with
Some k -> k
| None -> blob_locations.invalid_location
in
let blob_id_db = ml2int blob_id in
(* Revision parameters *)
let rev_id = ml2int revision_info.rev_id in
let page_id = ml2int revision_info.rev_page in
let text_id = ml2int revision_info.rev_text_id in
let time_string = ml2str revision_info.rev_timestamp in
let user_id = ml2int revision_info.rev_user in
let username = ml2str revision_info.rev_user_text in
let is_minor = ml2int (if revision_info.rev_is_minor then 1 else 0) in
(* Quality parameters *)
let q1 = ml2str (string_of__of__sexp_of sexp_of_qual_info_t quality_info) in
let q2 = ml2float quality_info.reputation_gain in
let aq2 = if (q2 = "inf") then (ml2float infinity) else q2 in
let q3 = ml2float quality_info.overall_trust in
(* Db write access *)
let s2 = Printf.sprintf "INSERT INTO %swikitrust_revision (revision_id, page_id, text_id, time_string, user_id, username, is_minor, quality_info, reputation_delta, overall_trust, blob_id) VALUES (%s, %s, %s, %s, %s, %s, %s, %s, %s, %s, %s) ON DUPLICATE KEY UPDATE quality_info = %s, reputation_delta = %s, overall_trust = %s, blob_id = %s, page_id = %s"
db_prefix rev_id page_id text_id time_string user_id username is_minor q1 aq2 q3 blob_id_db q1 aq2 q3 blob_id_db page_id in
ignore (self#db_exec mediawiki_dbh s2)
(** [read_revision_info rev_id] reads the wikitrust information
quality, and blob_id, of revision_id *)
method read_revision_quality (rev_id: int) : qual_info_t * int option =
let s = Printf.sprintf "SELECT quality_info, blob_id FROM %swikitrust_revision WHERE revision_id = %s" db_prefix (ml2int rev_id) in
let result = self#db_exec mediawiki_dbh s in
match fetch result with
None -> raise DB_Not_Found
| Some x -> begin
let q = of_string__of__of_sexp qual_info_t_of_sexp
(not_null str2ml x.(0)) in
let bid = not_null int2ml x.(1) in
let bid_opt =
if bid = blob_locations.invalid_location
then None
else Some bid
in (q, bid_opt)
end
(** [write_colored_markup page_id rev_id blob_id_opt page_open_blob markup]
writes the "colored" text [markup] of a revision. The [markup]
represents the main text of the revision, annotated with trust
and origin information. [page_id] and [rev_id] are as usual.
[blob_id_opt] specifies the blob in which the information should
be written, if known. Otherwise, the information is written in
[page_open_blob] blob. The function returns a pair, consisting of:
- The blob in which the revision was written
(this coincides with the content of [blob_id_opt] when the latter
is not null).
- The new open blob for the page (this may coincide with the old
open blob, of course).
*)
method write_colored_markup (page_id: int) (rev_id : int)
(blob_id_opt: int option) (page_open_blob: int)
(markup : string) : int * int =
(* Figures out in which blob to write the information. *)
let blob_id =
match blob_id_opt with
None -> page_open_blob
| Some bid -> bid
in
(* Validates blob_id *)
if blob_id < blob_locations.initial_location then
raise DB_Illegal_blob_id;
(* Writes the information in the blob, and writes the blob back to disk. *)
let blob_content_opt = self#read_blob page_id blob_id in
let (new_blob_content, new_n_revs_in_blob) =
Revision_store.add_revision_to_blob blob_content_opt rev_id markup in
self#write_blob page_id blob_id new_blob_content;
(* If we added the revision to an open blob, and this open blob has
become too large, then it opens a new blob for writing. *)
let new_page_open_blob = match blob_id_opt with
Some _ -> page_open_blob (* No change: we wrote to an old blob. *)
| None -> begin
(* We had to add to the open blob *)
let blob_size = String.length new_blob_content in
if blob_size >= blob_params.max_blob_size ||
(blob_size >= blob_params.min_blob_size &&
new_n_revs_in_blob >= blob_params.max_revs_per_blob) then begin
(* We start a new blob. *)
self#write_open_blob_id page_id (page_open_blob + 1);
page_open_blob + 1
end
else page_open_blob
end
in (blob_id, new_page_open_blob)
(** [read_colored_markup rev_id blob_id_opt] reads the text markup
of a revision with id [rev_id]. The markup is the text of the
revision, annotated with trust and origin information.
The revision can be found in [blob_id_opt] (if not None).
If the revision cannot be found, including if [blob_id_opt] is None,
the DB_Not_Found exception is raised. *)
method read_colored_markup (page_id: int) (rev_id : int)
(blob_id_opt: int option) : string =
let blob_id = begin match blob_id_opt with
None -> raise DB_Not_Found
| Some bid -> bid
end in
(* Validates the blob_id *)
if blob_id < blob_locations.initial_location then
raise DB_Illegal_blob_id;
let blob_content_opt = self#read_blob page_id blob_id in
match blob_content_opt with
None -> raise DB_Not_Found
| Some c -> begin
try Revision_store.read_revision_from_blob rev_id c
with Not_found -> raise DB_Not_Found
end
(** [write_trust_origin_sigs page_id rev_id page_sigs words trust
origin sigs] writes that the revision [rev_id] is associated
with [words], [trust], [origin], and [author_sigs]. The
function is given the page signatures [page_sigs], and does not
actually write things to disk; rather, it updates these
page_sigs in-place. *)
method write_words_trust_origin_sigs (page_id: int) (rev_id: int) (page_sigs: page_sig_t)
(words: string array)
(trust: float array)
(origin: int array)
(author: string array)
(author_sigs: Author_sig.packed_author_signature_t array) : page_sig_t =
let signature = {
words_a = words;
trust_a = trust;
origin_a = origin;
author_a = author;
sig_a = author_sigs;
} in
(* If the revision already has sigs, removes them *)
let l_purged = List.remove_assoc rev_id page_sigs in
(* Adds the new signatures *)
let l_added = (rev_id, signature) :: l_purged in
(* Assigns the new value *)
l_added
(** [read_words_trust_origin_sigs page_id rev_id page_sigs] reads
the words, trust, origin, and author sigs for the revision
[rev_id] of page [page_id], given the page sigs [page_sigs]. *)
method read_words_trust_origin_sigs (page_id: int) (rev_id: int)
(page_sigs: page_sig_t)
: (string array * float array * int array * string array * Author_sig.packed_author_signature_t array) =
if List.mem_assoc rev_id page_sigs
then begin
let signature = List.assoc rev_id page_sigs in
(signature.words_a, signature.trust_a, signature.origin_a, signature.author_a, signature.sig_a)
end else raise DB_Not_Found
(** [delete_author_sigs page_id rev_id page_sigs] removes from the
signatures [page_sigs] the signatures for [rev_id]. *)
method delete_author_sigs (page_id: int) (rev_id: int) (page_sigs: page_sig_t)
: page_sig_t =
List.remove_assoc rev_id page_sigs
(* Methods on standard revisions *)
(** [get_rev_text page_id rev_id text_id] returns the text associated with
text id [text_id] for revision [rev_id] *)
method read_rev_text (page_id: int) (rev_id: int) (text_id: int) : string =
match rev_base_path with
| None -> begin
let s = Printf.sprintf "SELECT old_text FROM %stext WHERE old_id = %s" db_prefix (ml2int text_id) in
let result = self#db_exec mediawiki_dbh s in
match Mysql.fetch result with
| None -> raise DB_Not_Found
| Some y -> not_null str2ml y.(0)
end
| Some b -> begin
let result = Filesystem_store.read_revision b page_id rev_id in
match result with
| None -> raise DB_Not_Found
| Some r -> r
end
(* ================================================================ *)
(* User methods. *)
(** [inc_rep uid delta uname] increments the reputation of user [uid] by
[delta] in a single operation, so to avoid database problems.
[uname] is the username of the user, to ensure that we know
the names of the users. *)
method inc_rep (uid : int) (delta : float) (uname: string) =
let s = Printf.sprintf "INSERT INTO %swikitrust_user (user_id, user_rep, username) VALUES (%s, %s, %s) ON DUPLICATE KEY UPDATE user_rep = user_rep + %s"
db_prefix
(ml2int uid) (ml2float delta) (ml2str uname) (ml2float delta) in
ignore (self#db_exec mediawiki_dbh s)
(** [set_rep uid rep uname] sets the fact that the reputation for [uid]
is [rep], and the username is [uname]. *)
method set_rep (uid : int) (rep : float) (uname: string) =
let s = Printf.sprintf "REPLACE INTO %swikitrust_user (user_id, user_rep, username) VALUES (%s, %s, %s)"
db_prefix (ml2int uid) (ml2float rep) (ml2str uname) in
ignore (self#db_exec mediawiki_dbh s)
(** [get_rep uid] gets the reputation of user [uid], from a table
relating user ids to their reputation
@raise DB_Not_Found if no tuple is returned by the database.
*)
method get_rep (uid : int) : float =
let s = Printf.sprintf "SELECT user_rep FROM %swikitrust_user WHERE user_id = %s" db_prefix (ml2int uid) in
let result = self#db_exec mediawiki_dbh s in
match Mysql.fetch result with
None -> raise DB_Not_Found
| Some x -> not_null float2ml x.(0)
(** [get_user_id name] gets the user id for the user with the given
user name *)
method get_user_id (user_name : string) : int =
let s = Printf.sprintf "SELECT user_id FROM %swikitrust_user WHERE username = %s" db_prefix (ml2str user_name) in
let result = self#db_exec mediawiki_dbh s in
begin
match Mysql.fetch result with
None -> raise DB_Not_Found
| Some x -> not_null int2ml x.(0)
end
(** [write_user_id user_name] writes that the user with
name [user_name]. and returns the new uid *)
method write_user_id (user_name: string) : int =
let s = Printf.sprintf "INSERT INTO %swikitrust_user (username) VALUES (%s) ON DUPLICATE KEY UPDATE username = %s" db_prefix (ml2str user_name) (ml2str user_name) in
ignore (self#db_exec mediawiki_dbh s);
Int64.to_int (insert_id mediawiki_dbh)
(* ================================================================ *)
(* Votes. *)
(** Add the vote to the db *)
method vote (vote : vote_t) =
let s = Printf.sprintf "INSERT INTO %swikitrust_vote (revision_id, page_id, voter_name, voted_on) VALUES (%s, %s, %s, %s)" db_prefix (ml2int vote.vote_revision_id) (ml2int vote.vote_page_id) (ml2str vote.vote_voter_name) (ml2str vote.vote_time) in
ignore (self#db_exec mediawiki_dbh s)
(* ================================================================ *)
(* Server System *)
(* The following methods are used in the remote use of WikiTrust. *)
(** [mark_page_to_process page_id page_title] specifies that a page
must be brought up to date, due to a vote or a new revision. *)
method mark_page_to_process (page_id : int) (page_title : string) : unit =
let s = Printf.sprintf "INSERT INTO %swikitrust_queue (revision_id, page_id) VALUES (%s, %s) ON DUPLICATE KEY UPDATE requested_on = now()" db_prefix (ml2int page_id) (ml2str page_title) in
ignore (self#db_exec mediawiki_dbh s)
(** [mark_page_as_processed page_id] marks that a page has been processed. *)
method mark_page_as_processed (page_id : int) : unit =
let s = Printf.sprintf "DELETE FROM %swikitrust_queue WHERE page_id = %s" db_prefix (ml2int page_id) in
ignore (self#db_exec mediawiki_dbh s);
(* Mark that we are done with this processing unit. *)
self#release_reservation db_name;
(* TODO: make sure that a processed page has its title
* updated correctly. *)
(** [mark_page_as_unprocessed page_id] marks that a page has not
been fully processed. *)
method mark_page_as_unprocessed (page_id : int) =
let s = Printf.sprintf "UPDATE %swikitrust_queue SET processed = 'unprocessed' WHERE page_id = %s" db_prefix (ml2int page_id) in
ignore (self#db_exec mediawiki_dbh s)
(** [fetch_work_from_queue max_to_get n_retries] gets the
list of page ids and titles that have to be brought up to date.
It also marks those pages as "processing", so that
subsequent requests do not return the same revisions. This code
contains a transaction start / commit pair. [max_to_get] is the
maximum number of results to get; [n_retries] is the number of
times the start / commit pair is used. *)
method fetch_work_from_queue (max_to_get : int) (n_retries: int)
(max_procs : int)
: (int * string) list =
let n_attempts = ref 0 in
let results = ref [] in
let results_arr = ref [|(0,"")|] in
while !n_attempts < n_retries do
begin
try
self#start_transaction;
let s = Printf.sprintf "SELECT page_id, page_title FROM %swikitrust_queue WHERE processed = 'unprocessed' AND priority > 0 ORDER BY priority DESC LIMIT %s"
db_prefix (ml2int max_to_get) in
let get_id row : int = (not_null int2ml row.(0)) in
let get_title row : string = ExtString.String.map (fun c -> if c = '_' then ' ' else c)
(not_null str2ml row.(1)) in
let get_pair row = (get_id row, get_title row) in
results := Mysql.map (self#db_exec mediawiki_dbh s) get_pair;
let mark_as_processing (page_id, _) =
let s = Printf.sprintf "UPDATE %swikitrust_queue SET processed = 'processing' WHERE page_id = %s" db_prefix (ml2int page_id) in
ignore (self#db_exec mediawiki_dbh s)
in
if (List.length !results) > 0 then (
let num_availible = self#acquire_reservations db_name
(List.length !results) max_procs in
assert (num_availible <= (List.length !results));
results_arr := Array.sub (Array.of_list !results) 0 num_availible;
Array.iter mark_as_processing !results_arr
) else (
results_arr := Array.of_list !results
);
(* We need to end this loop. *)
self#commit;
n_attempts := n_retries
with