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本篇文章為大家展示了如何用ElasticSearch實(shí)現(xiàn)基于標(biāo)簽的興趣推薦，內(nèi)容簡(jiǎn)明扼要并且容易理解，絕對(duì)能使你眼前一亮，通過(guò)這篇文章的詳細(xì)介紹希望你能有所收獲。
下面將通過(guò)ElasticSearch（簡(jiǎn)稱(chēng)ES）倒排索引的特性實(shí)現(xiàn)基于標(biāo)簽的興趣推薦
操作系統(tǒng)：ubuntu 20.04
Docker version 19.03.8
ElasticSearch 7.X
Curl工具，推薦Insomnia
ES GUI工具， 推薦appbaseio/dejavu
文章索引中有字段tags，存儲(chǔ)了文章有關(guān)的標(biāo)簽
每個(gè)用戶都有自己的興趣標(biāo)簽tags
興趣推薦就是用興趣標(biāo)簽去匹配文章的標(biāo)簽，用戶的一個(gè)興趣標(biāo)簽命中N篇文章，用戶的多個(gè)興趣標(biāo)簽命中M篇文章，M和N有交叉，即文章中有重復(fù)，重復(fù)出現(xiàn)次數(shù)最多的文章就是最貼近用戶興趣的。原理理解起來(lái)簡(jiǎn)單，使用ES的目的是解決快速查詢(xún)和排序的問(wèn)題。
docker環(huán)境安裝單機(jī)版ES，用來(lái)測(cè)試
docker run -d --name elasticsearch -v /home/cherokee/docker-data/es-data:/usr/share/elasticsearch/data -e http.cors.enabled=true -e http.cors.allow-origin="*" -e http.cors.allow-headers=X-Requested-With,X-Auth-Token,Content-Type,Content-Length,Authorization -e http.cors.allow-credentials=true -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" successage/es-ik
在本地啟動(dòng)了ES服務(wù)，通過(guò) http://localhost:9200 可以訪問(wèn)
創(chuàng)建一個(gè)名為rcmd的索引
curl --request PUT \ --url http://localhost:9200/rcmd
curl --request PUT \
--url http://localhost:9200/rcmd/_mapping \
--header 'content-type: application/json' \
--data '{
"properties": {
"tags": {
"type": "keyword",
"store": true
},
"update_time": {
"type": "date",
"store": true
}
}
}'兩個(gè)字段：
tags，文章的興趣標(biāo)簽，keyword類(lèi)型就是不需要全文檢索，標(biāo)簽以數(shù)組的形式存放
update_time，更新時(shí)間，這是給興趣推薦加一個(gè)額外的排序條件，實(shí)際項(xiàng)目中往往是需要結(jié)合時(shí)間和匹配度來(lái)排序的
插入一些數(shù)據(jù)
curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
],
"update_time": "2020-06-01T00:02:11.030"
}'再插入一條，同樣標(biāo)簽，但是時(shí)間不一樣，后面例子中有妙用
curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
],
"update_time": "2020-07-01T00:02:11.030"
}'curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"啤酒",
"米酒",
"飲料",
"餐飲",
"生活"
],
"update_time": "2020-06-02T00:02:11.030"
}'curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"火鍋",
"自助餐",
"外賣(mài)",
"燒烤",
"餐飲"
],
"update_time": "2020-06-03T00:02:11.030"
}'curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"太陽(yáng)",
"月亮",
"大海",
"星星",
"自然"
],
"update_time": "2020-06-01T00:02:11.030"
}'curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"人類(lèi)",
"動(dòng)物",
"植物",
"地球",
"自然"
],
"update_time": "2020-06-01T00:02:11.030"
}'curl --request POST \
--url http://localhost:9200/rcmd/_doc \
--header 'content-type: application/json' \
--data '{
"tags": [
"男人",
"女人",
"小孩",
"老人",
"人類(lèi)"
],
"update_time": "2020-06-02T00:02:11.030"
}'最終數(shù)據(jù)如下 
curl --request POST \
--url http://localhost:9200/rcmd/_search \
--header 'content-type: application/json' \
--data '{
"query": {
"bool": {
"should": [
{
"constant_score": {
"boost": 1,
"filter": {
"match": {
"tags": "生活"
}
}
}
},
{
"constant_score": {
"boost": 1,
"filter": {
"match": {
"tags": "衣服"
}
}
}
},
{
"constant_score": {
"boost": 1,
"filter": {
"match": {
"tags": "火鍋"
}
}
}
}
]
}
}
}'should表達(dá)式的意義是匹配“生活”、“衣服”、“火鍋”三個(gè)標(biāo)簽中任何一個(gè)的文章都可以返回。用constant_score查詢(xún)，如果某個(gè)文章涵蓋標(biāo)簽越多分值就越高。也就是說(shuō)如果某個(gè)文章標(biāo)簽完全涵蓋了這三個(gè)標(biāo)簽，那么它的分值最高的。查詢(xún)結(jié)果如下：
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 2.0,
"hits": [
{
"_index": "rcmd",
"_type": "_doc",
"_id": "brQO63MBTdXKc2eArv9A",
"_score": 2.0,
"_source": {
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
],
"update_time": "2020-06-01T00:02:11.030"
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "b7QP63MBTdXKc2eAPf_Y",
"_score": 2.0,
"_source": {
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
],
"update_time": "2020-07-01T00:02:11.030"
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "cLQQ63MBTdXKc2eA6_8v",
"_score": 1.0,
"_source": {
"tags": [
"啤酒",
"米酒",
"飲料",
"餐飲",
"生活"
],
"update_time": "2020-06-02T00:02:11.030"
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "cbQS63MBTdXKc2eAcP-N",
"_score": 1.0,
"_source": {
"tags": [
"火鍋",
"自助餐",
"外賣(mài)",
"燒烤",
"餐飲"
],
"update_time": "2020-06-03T00:02:11.030"
}
}
]
}
}有兩篇文章涵蓋了其中兩個(gè)標(biāo)簽“生活”和“衣服”，得分為2，排到了前面。這個(gè)排序基本滿足了興趣匹配的要求。
實(shí)際的項(xiàng)目中往往是用戶的興趣標(biāo)簽的權(quán)值不一樣，假設(shè)用戶的興趣標(biāo)簽是["火鍋","生活","衣服"]，排在越前面的權(quán)重越高，查詢(xún)的時(shí)候需要給關(guān)鍵詞設(shè)定權(quán)重，上面的查詢(xún)語(yǔ)句所有boost都是默認(rèn)值1，現(xiàn)在根據(jù)需求改動(dòng)權(quán)值再查詢(xún)。
curl --request POST \
--url http://localhost:9200/rcmd/_search \
--header 'content-type: application/json' \
--data '{
"query": {
"bool": {
"should": [
{
"constant_score": {
"boost": 1,
"filter": {
"match": {
"tags": "生活"
}
}
}
},
{
"constant_score": {
"boost": 4,
"filter": {
"match": {
"tags": "衣服"
}
}
}
},
{
"constant_score": {
"boost": 6,
"filter": {
"match": {
"tags": "火鍋"
}
}
}
}
]
}
}
}'分別給三個(gè)詞加上權(quán)重6、4、1，查詢(xún)結(jié)果如下：
{
"took": 1,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 6.0,
"hits": [
{
"_index": "rcmd",
"_type": "_doc",
"_id": "cbQS63MBTdXKc2eAcP-N",
"_score": 6.0,
"_source": {
"tags": [
"火鍋",
"自助餐",
"外賣(mài)",
"燒烤",
"餐飲"
],
"update_time": "2020-06-03T00:02:11.030"
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "brQO63MBTdXKc2eArv9A",
"_score": 5.0,
"_source": {
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
],
"update_time": "2020-06-01T00:02:11.030"
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "b7QP63MBTdXKc2eAPf_Y",
"_score": 5.0,
"_source": {
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
],
"update_time": "2020-07-01T00:02:11.030"
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "cLQQ63MBTdXKc2eA6_8v",
"_score": 1.0,
"_source": {
"tags": [
"啤酒",
"米酒",
"飲料",
"餐飲",
"生活"
],
"update_time": "2020-06-02T00:02:11.030"
}
}
]
}
}可以看到包含“火鍋”的文章排到了第一，包含“衣服”和“生活”的文章雖然兩個(gè)詞都命中，但是在權(quán)值的弱化之下排到了第二第三位。
curl --request POST \
--url http://localhost:9200/rcmd/_search \
--header 'content-type: application/json' \
--data '{
"query": {
"function_score": {
"query": {
"bool": {
"must": [
{
"range": {
"update_time": {
"from": "2020-06-01",
"to": "2020-08-01"
}
}
},
{
"bool": {
"should": [
{
"term": {
"tags": {
"term": "火鍋",
"boost": 2
}
}
},
{
"term": {
"tags": {
"term": "衣服",
"boost": 1
}
}
},
{
"term": {
"tags": {
"term": "生活",
"boost": 1
}
}
}
]
}
}
]
}
},
"functions": [
{
"gauss": {
"update_time": {
"scale": "3d",
"origin": "2020-07-02T00:01:00.000"
}
}
}
]
}
},
"_source": {
"include": [
"tags",
"update_time"
]
},
"from": 0,
"size": 10
}'以上是相對(duì)完整的一個(gè)查詢(xún)，首先對(duì)update_time發(fā)布時(shí)間做了限制，只選擇一定范圍內(nèi)的數(shù)據(jù)，隨后是標(biāo)簽的匹配，多個(gè)標(biāo)簽匹配條件之間是"OR"的關(guān)系，標(biāo)簽具有不同的權(quán)重，接下來(lái)用衰減函數(shù)gauss對(duì)update_time做衰減排序，衰減函數(shù)的意義是越近越好，scale": "3d"就是以3天為一個(gè)階梯先對(duì)數(shù)據(jù)進(jìn)行排序，相同階梯內(nèi)的數(shù)據(jù)再按照標(biāo)簽匹配度排序。 注：gauss中的origin可以不指定 最終的查詢(xún)結(jié)果：
{
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 3.6649413,
"hits": [
{
"_index": "rcmd",
"_type": "_doc",
"_id": "b7QP63MBTdXKc2eAPf_Y",
"_score": 3.6649413,
"_source": {
"update_time": "2020-07-01T00:02:11.030",
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
]
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "cbQS63MBTdXKc2eAcP-N",
"_score": 4.4511746E-28,
"_source": {
"update_time": "2020-06-03T00:02:11.030",
"tags": [
"火鍋",
"自助餐",
"外賣(mài)",
"燒烤",
"餐飲"
]
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "cLQQ63MBTdXKc2eA6_8v",
"_score": 1.764942E-30,
"_source": {
"update_time": "2020-06-02T00:02:11.030",
"tags": [
"啤酒",
"米酒",
"飲料",
"餐飲",
"生活"
]
}
},
{
"_index": "rcmd",
"_type": "_doc",
"_id": "brQO63MBTdXKc2eArv9A",
"_score": 2.8566082E-32,
"_source": {
"update_time": "2020-06-01T00:02:11.030",
"tags": [
"布料",
"抹布",
"褲子",
"衣服",
"生活"
]
}
}
]
}
}同樣是匹配了“衣服”和“生活”的兩篇文章，一篇在最前面，一篇在最后面，是因?yàn)閡pdate_time的緣故，一篇是7月1日發(fā)布的，另一篇在6月1日，不在同一時(shí)間階梯內(nèi)，日期久遠(yuǎn)的排到了后面。中間的兩篇，各自匹配了一個(gè)標(biāo)簽，分別是“燒烤”和“生活”，兩篇文章時(shí)間階梯沒(méi)有明顯的區(qū)別，然而匹配“火鍋”的排到了前面，是因?yàn)椤盎疱仭钡年P(guān)鍵詞加了較高的權(quán)重。 至此，我們實(shí)現(xiàn)了按照標(biāo)簽匹配文章，并且結(jié)合了時(shí)間因素和匹配度評(píng)分的興趣推薦。
以上例子沒(méi)有在超大數(shù)據(jù)環(huán)境下測(cè)試過(guò)，還沒(méi)有具體的性能指標(biāo)。
上述內(nèi)容就是如何用ElasticSearch實(shí)現(xiàn)基于標(biāo)簽的興趣推薦，你們學(xué)到知識(shí)或技能了嗎？如果還想學(xué)到更多技能或者豐富自己的知識(shí)儲(chǔ)備，歡迎關(guān)注億速云行業(yè)資訊頻道。
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