我是否有理由通过包含SHA1 hexdigests的字符串列进行选择？

Question

我有一个看起来像这样的邀请表

sqlite> .schema invitations
CREATE TABLE "invitations" 
    ( "id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL
    , "sender_id" integer
    , "recipient_email" varchar(255)
    , "token" varchar(255)
    , "sent_at" datetime
    , "team_id" integer
    , "created_at" datetime
    , "updated_at" datetime
    );

CREATE UNIQUE INDEX "index_invitations_on_recipient_email_and_team_id"
    ON "invitations" ("recipient_email", "team_id");

CREATE INDEX "index_invitations_on_sender_id"
    ON "invitations" ("sender_id");

CREATE INDEX "index_invitations_on_team_id"
    ON "invitations" ("team_id");

令牌列存储在记录创建时生成的hexdigests(Ruby):

self.token = Digest::SHA1.hexdigest([Time.now, rand].join)

当我将邀请插入数据库时​​,我可以使用它来检索它

SELECT * FROM "invitations" where "invitations"."recipient_email" = "an email"

但

SELECT * FROM "invitations" where "invitations"."token" = "an token"

即使我从insert语句中复制/粘贴确切的标记,也会注意到？

编辑
事实证明

SELECT * FROM "invitations" where "invitations"."token" LIKE "an token"

将正确地检索记录.

为什么"喜欢"工作,但"="不工作？我已尝试在插入之前剥离十六进制并执行不区分大小写的选择.都没有奏效.

编辑2 似乎我只能使用rubygem"sqlite3"和命令行来复制这个问题.那是没有Rails等.

这是过程:

stuff $ gem install sqlite3
Fetching: sqlite3-1.3.3.gem (100%)
Building native extensions.  This could take a while...
Successfully installed sqlite3-1.3.3
1 gem installed
Installing ri documentation for sqlite3-1.3.3...
Installing RDoc documentation for sqlite3-1.3.3...
stuff $ irb
ruby-1.9.2-head :001 > require "sqlite3"
ruby-1.9.2-head :017 > rows = db.execute <<-SQL
ruby-1.9.2-head :018"> create table invitations (
ruby-1.9.2-head :019"> token varchar(40)
ruby-1.9.2-head :020"> );
ruby-1.9.2-head :021"> SQL
# with normal strings for comparison
ruby-1.9.2-head :022 > ['4535435', 'jfeu833'].each {|hash| db.execute "insert into 'invitations' ('token') values (?)", hash }
 => ["4535435", "jfeu833"] 
ruby-1.9.2-head :023 > db.execute("select * from invitations where invitations.token = '4535435'") {|row| p row }
# it finds the row successfully
["4535435"]
 => #<SQLite3::Statement:0x000001011741c8> 
ruby-1.9.2-head :028 > require "digest/sha1"
 => true 
# now to try it with a hash
ruby-1.9.2-head :029 > [Digest::SHA1.hexdigest("banana")].each {|hash| db.execute "insert into 'invitations' ('token') values (?)", hash }
 => ["250e77f12a5ab6972a0895d290c4792f0a326ea8"]
ruby-1.9.2-head :031 > db.execute("select * from invitations where invitations.token = '250e77f12a5ab6972a0895d290c4792f0a326ea8'") {|row| p row }
# notice that no record is printed
 => #<SQLite3::Statement:0x0000010107c630> 

Answer 1

我在聊天中与duckyfuzz(OP)讨论过这个问题,我们发现哈希在sqlite中存储为BLOB:

sqlite> select typeof(token) from invitations; 
blob 
blob

所以出于某种原因,尽管ruby说插入的是一个字符串:

irb(main):002:0> (Digest::SHA1.hexdigest("banana")).class() 
=> String

它最终在sqlite中作为BLOB.

插值或插入文字而不是使用参数插入会使问题消失(由OP测试):

oh ok got it
ruby-1.9.2-head :010 > db.execute("insert into invitations (token) VALUES ('#{the_hash}')") 
=> []
ok now the dump..

INSERT INTO "invitations" VALUES('bda04628ea94f26cac0793eac103258eb515c505');
much better!

问题是由二进制字符串将由 sqlite3 ruby​​gem 存储为blob的事实引起的.防止这种情况的方法是在插入之前将散列编码为UTF-8.

hash = Digest::SHA1.hexdigest("banana").encode("UTF-8")
db.execute("insert into invitations (token) values (?)", hash)

完成后,哈希将存储为文本.