# Simple autocomplete with Manticore 本文描述了在 Manticore Search 中实现词补全的一种方法。 # 什么是自动补全？ 自动补全（或词补全）是一种功能，允许应用程序在用户输入时预测剩余的单词。通常的工作方式是：用户在搜索栏中开始输入一个单词，然后会弹出一个包含建议的下拉菜单，用户可以从列表中选择一个。 建议的来源可以是各种各样的。最好是显示的单词或句子在现有的数据集中可用，这样用户不会选择返回空结果的内容。但在某些情况下，自动补全基于之前的（成功）搜索，理论上可能找不到结果，但仍可能有意义。这取决于您应用程序的具体情况。 最简单的自动补全可以通过从数据集中项目标题中查找建议来实现。这可以是文章/新闻的标题、产品的名称，或者正如我们很快将展示的电影名称。为此，我们需要将字段定义为 [字符串属性](https://docs.manticoresearch.com/latest/html/conf_options_reference/data_source_configuration_options.html#sql-attr-string) 或 [存储字段](https://play.manticoresearch.com/docstore/)，以避免在原始数据中进行额外的查找。 由于用户需要提供一个不完整的单词，我们需要执行通配符搜索。可以通过在索引中启用前缀匹配或中缀匹配来实现通配符搜索。由于这可能 [影响响应时间](https://docs.manticoresearch.com/latest/html/conf_options_reference/index_configuration_options.html?_ga=2.5400947.1963281054.1585565336-1675027090.1585565336#min-infix-len)，您需要决定是否要在用于搜索的索引中启用它，或者仅在专门用于自动补全功能的索引中启用。另一个原因是为了使后者尽可能紧凑，以提供最小的延迟，这对于自动补全的用户体验尤为重要。通常我们会将通配符星号添加到右侧，因为我们假设用户开始输入一个单词，但为了更广泛的结果，我们会在两侧都添加星号以获取可能具有前缀的单词。在本教程中，对于电影数据集，我们选择中缀匹配，因为它还启用了用于单词更正的 SUGGEST 功能（[参见此教程](https://play.manticoresearch.com/didyoumean/) 中的说明）。我们的索引声明将是： ```ini index movies { type = plain path = /var/lib/manticore/data/movies source = movies min_infix_len = 3 } ``` 由于我们将从电影标题提供自动补全，我们的查询将仅限于 'movie_title' 字段。 ## 电影标题的自动补全 --- 您的应用程序前端可以在搜索框中输入第一个字符时开始查询建议。然而，如果索引非常大，这可能会对系统造成更大的压力，因为它将向服务器发送更多请求，而且 1-2 个字符的通配符搜索可能较慢。假设用户输入 'sha'。 ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title sha*'); +------+---------------------------------------+ | id | movie_title | +------+---------------------------------------+ | 118 | A Low Down Dirty Shame | | 394 | Austin Powers: The Spy Who Shagged Me | | 604 | Book of Shadows: Blair Witch 2 | | 951 | Dark Shadows | | 1318 | Fifty Shades of Black | | 1319 | Fifty Shades of Grey | | 1389 | Forty Shades of Blue | | 1853 | In the Shadow of the Moon | | 1928 | Jack Ryan: Shadow Recruit | | 3114 | Shade | | 3115 | Shadow Conspiracy | | 3116 | Shadow of the Vampire | | 3117 | Shadowlands | | 3118 | Shaft | | 3119 | Shakespeare in Love | | 3120 | Shalako | | 3121 | Shall We Dance | | 3122 | Shallow Hal | | 3123 | Shame | | 3124 | Shanghai Calling | +------+---------------------------------------+ 20 rows in set (0.00 sec) ``` 我们主要关注电影标题，因此不会返回所有列。正如我们所见，返回了大量结果。我们可以通过例如按 Facebook 喜欢数进行二次排序来调整查询，但此时还太早做出用户正在寻找什么的准确猜测： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title sha*') ORDER BY WEIGHT() DESC, cast_total_facebook_likes DESC; +------+--------------------------------------------------+ | id | movie_title | +------+--------------------------------------------------+ | 951 | Dark Shadows | | 3131 | Shark Tale | | 394 | Austin Powers: The Spy Who Shagged Me | | 3118 | Shaft | | 4326 | The Shaggy Dog | | 3142 | Sherlock Holmes: A Game of Shadows | | 3134 | Shattered | | 3123 | Shame | | 3525 | The Adventures of Sharkboy and Lavagirl 3-D | | 3117 | Shadowlands | | 3129 | Shark Lake | | 4328 | The Shawshank Redemption | | 3494 | Teenage Mutant Ninja Turtles: Out of the Shadows | | 3135 | Shattered Glass | | 3130 | Shark Night 3D | | 1319 | Fifty Shades of Grey | | 4619 | Tristram Shandy: A Cock and Bull Story | | 118 | A Low Down Dirty Shame | | 3132 | Sharknado | | 1318 | Fifty Shades of Black | +------+--------------------------------------------------+ 20 rows in set (0.00 sec) ``` 假设用户输入另一个字母： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title shaf*') ORDER BY WEIGHT() DES , cast_total_facebook_likes DESC; +------+-------------+ | id | movie_title | +------+-------------+ | 3118 | Shaft | +------+-------------+ 1 row in set (0.00 sec) ``` 现在我们只有一个结果。 让我们再举一个例子，假设我们输入 'shad*'。 ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title shad*') ORDER BY WEIGHT() DES , cast_total_facebook_likes DESC; +------+--------------------------------------------------+ | id | movie_title | +------+--------------------------------------------------+ | 951 | Dark Shadows | | 3142 | Sherlock Holmes: A Game of Shadows | | 3117 | Shadowlands | | 3494 | Teenage Mutant Ninja Turtles: Out of the Shadows | | 1319 | Fifty Shades of Grey | | 1318 | Fifty Shades of Black | | 4325 | The Shadow | | 3115 | Shadow Conspiracy | | 3116 | Shadow of the Vampire | | 1928 | Jack Ryan: Shadow Recruit | | 1389 | Forty Shades of Blue | | 604 | Book of Shadows: Blair Witch 2 | | 3114 | Shade | | 1853 | In the Shadow of the Moon | | 4353 | The Sound and the Shadow | +------+--------------------------------------------------+ 15 rows in set (0.00 sec) ``` 然后输入 `shado*`： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title shado*') ORDER BY WEIGHT() DE C, cast_total_facebook_likes DESC; +------+--------------------------------------------------+ | id | movie_title | +------+--------------------------------------------------+ | 951 | Dark Shadows | | 3142 | Sherlock Holmes: A Game of Shadows | | 3117 | Shadowlands | | 3494 | Teenage Mutant Ninja Turtles: Out of the Shadows | | 4325 | The Shadow | | 3115 | Shadow Conspiracy | | 3116 | Shadow of the Vampire | | 1928 | Jack Ryan: Shadow Recruit | | 604 | Book of Shadows: Blair Witch 2 | | 1853 | In the Shadow of the Moon | | 4353 | The Sound and the Shadow | +------+--------------------------------------------------+ 11 rows in set (0.00 sec) ``` 以及 'shadow'： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title shadow') ORDER BY WEIGHT() DE C, cast_total_facebook_likes DESC; +------+---------------------------+ | id | movie_title | +------+---------------------------+ | 4325 | The Shadow | | 3115 | Shadow Conspiracy | | 3116 | Shadow of the Vampire | | 1928 | Jack Ryan: Shadow Recruit | | 1853 | In the Shadow of the Moon | | 4353 | The Sound and the Shadow | +------+---------------------------+ 6 rows in set (0.00 sec) ``` 假设用户正在寻找 'shadow' 作为第一个词，他将继续输入另一个词，例如 'shadow c'： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title shadow c*') ORDER BY WEIGHT() DESC, cast_total_facebook_likes DESC; +------+-------------------+ | id | movie_title | +------+-------------------+ | 3115 | Shadow Conspiracy | +------+-------------------+ 1 row in set (0.01 sec) ``` 在这种情况下，我们得到一个结果，应该能满足用户，但在其他情况下可能会得到更多结果，用户将继续输入字母，就像第一个词一样，Manticore 会根据输入返回更多建议： ![img](./simple-autocomplete-with-manticore/phantom.gif) ## 添加更多过滤条件 --- 在之前的示例中，匹配项的唯一限制是必须是指定字段的一部分。如果我们想要，可以实现更严格的自动补全。 例如，这里我们获取以 'americ' 开头的匹配项，如 'American Hustle'，还有 'Captain America: Civil War'： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title americ* ') ORDER BY WEIGHT() D SC, cast_total_facebook_likes DESC; +------+---------------------------------------------------+ | id | movie_title | +------+---------------------------------------------------+ | 277 | American Hustle | | 701 | Captain America: Civil War | | 703 | Captain America: The Winter Soldier | | 282 | American Psycho | | 2612 | Once Upon a Time in America | | 272 | American Gangster | | 702 | Captain America: The First Avenger | | 269 | American Beauty | | 478 | Beavis and Butt-Head Do America | | 284 | American Sniper | | 4036 | The Legend of Hell's Gate: An American Conspiracy | | 273 | American Graffiti | | 285 | American Splendor | | 274 | American Heist | | 287 | America's Sweethearts | | 283 | American Reunion | | 280 | American Pie | | 281 | American Pie 2 | | 271 | American Dreamz | | 286 | American Wedding | +------+---------------------------------------------------+ 20 rows in set (0.00 sec) ``` 我们可以使用起始字段运算符仅显示以输入项开头的记录： ```sql MySQL [(none)]> SELECT id, movie_title FROM movies WHERE MATCH('@movie_title ^americ* ') ORDER BY WEIGHT() ESC, cast_total_facebook_likes DESC; +------+-------------------------------------+ | id | movie_title | +------+-------------------------------------+ | 277 | American Hustle | | 282 | American Psycho | | 272 | American Gangster | | 269 | American Beauty | | 284 | American Sniper | | 273 | American Graffiti | | 285 | American Splendor | | 274 | American Heist | | 287 | America's Sweethearts | | 283 | American Reunion | | 280 | American Pie | | 281 | American Pie 2 | | 271 | American Dreamz | | 286 | American Wedding | | 276 | American History X | | 268 | America Is Still the Place | | 279 | American Outlaws | | 275 | American Hero | | 278 | American Ninja 2: The Confrontation | | 270 | American Desi | +------+-------------------------------------+ 20 rows in set (0.00 sec) ``` 我们还需要考虑重复项。这在我们想要在没有唯一值的字段上进行自动补全时更为重要。例如，让我们尝试通过演员名称进行自动补全： ```sql MySQL [(none)]> SELECT actor_1_name FROM movies WHERE MATCH('@actor_1_name john* '); +--------------------+ | actor_1_name | +--------------------+ | Johnny Depp | | Johnny Depp | | Johnny Depp | | Dwayne Johnson | | Johnny Depp | | Johnny Depp | | Don Johnson | | Dwayne Johnson | | Johnny Depp | | Johnny Depp | | Johnny Depp | | Johnny Depp | | Johnny Depp | | Dwayne Johnson | | Johnny Depp | | Johnny Depp | | R. Brandon Johnson | | Dwayne Johnson | | Johnny Depp | | Johnny Depp | +--------------------+ 20 rows in set (0.09 sec) ``` 我们可以看到很多重复项。可以通过在该字段上进行分组来解决这个问题——假设我们将其作为字符串属性： ```sql MySQL [(none)]> SELECT actor_1_name FROM movies WHERE MATCH('@actor_1_name john* ') GROUP BY actor_1_name; [AMySQL [(none)]> SELECT actor_1_name FROM movies WHERE MATCH('@actor_1_name john* ') GROUP BY actor_1_name; +------------------------+ | actor_1_name | +------------------------+ | Johnny Depp | | Dwayne Johnson | | Don Johnson | | R. Brandon Johnson | | Johnny Pacar | | Kenny Johnston | | Johnny Cannizzaro | | Nicole Randall Johnson | | Johnny Lewis | | Richard Johnson | | Bill Johnson | | Eric Johnson | | John Belushi | | John Cothran | | John Ratzenberger | | John Cameron Mitchell | | John Saxon | | John Gatins | | John Boyega | | John Michael Higgins | +------------------------+ 20 rows in set (0.10 sec) ``` ## 高亮显示 --- 自动补全查询可以返回包含高亮显示的结果。虽然也可以在应用程序端执行高亮显示，但 Manticore Search 的高亮显示更强大，因为它会遵循搜索查询（相同的分词设置，[查询中的 AND、OR 和 NOT 等](https://play.manticoresearch.com/fulltextintro/)）。以之前的示例为例，我们只需要使用 'SNIPPET' 函数： ```sql MySQL [(none)]> SELECT SNIPPET(actor_1_name,' john*') FROM movies WHERE MATCH('@actor_1_name john* ') GROUP BY actor_1_name ORDER BY WEIGHT() DESC, cast_total_facebook_likes DESC; +--------------------------------+ | snippet(actor_1_name,' john*') | +--------------------------------+ | Johnny Depp | | Dwayne Johnson | | Johnny Pacar | | Don Johnson | | Johnny Cannizzaro | | Johnny Lewis | | Eric Johnson | | Nicole Randall Johnson | | Kenny Johnston | | R. Brandon Johnson | | Bill Johnson | | Richard Johnson | | John Ratzenberger | | John Belushi | | John Cameron Mitchell | | John Cothran | | Olivia Newton-John | | John Michael Higgins | | John Witherspoon | | John Amos | +--------------------------------+ 20 rows in set (0.00 sec) ``` 有关高亮显示的更多信息，请参阅 [此教程](https://play.manticoresearch.com/highlighting/)。 除了使用前缀和后缀之外，Manticore 还有其他实现自动补全的方法：使用 [CALL KEYWORDS](https://docs.manticoresearch.com/latest/html/sphinxql_reference/call_keywords_syntax.html)，开启或关闭 [bigram_index](https://docs.manticoresearch.com/latest/html/conf_options_reference/index_configuration_options.html#bigram-index)，使用 [CALL QSUGGEST](https://docs.manticoresearch.com/latest/html/sphinxql_reference/call_qsuggest_syntax.html)/[CALL SUGGEST](https://docs.manticoresearch.com/latest/html/sphinxql_reference/call_suggest_syntax.html)。但本文中展示的方法似乎是最容易上手的。如果你想尝试 Manticore Search，可以使用我们的 [docker image](https://hub.docker.com/r/manticoresearch/manticore)，它包含一个单行命令，可以在几秒钟内在任何服务器上运行 Manticore。 [在线查看完整的 Autocomplete 演示示例](https://play.manticoresearch.com/simpleautocomplete/)。