Search server for json files

6 years ago · 0b55f3cc43
13 changed files with 1134 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
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+.stack-work/
+json-search-server.cabal
+
+*~
+dist
+dist-*
+cabal-dev
+*.o
+*.hi
+*.chi
+*.chs.h
+*.dyn_o
+*.dyn_hi
+.hpc
+.hsenv
+.cabal-sandbox/
+cabal.sandbox.config
+*.prof
+*.aux
+*.hp
+*.eventlog
+cabal.project.local
+.HTF/
+.ghc.environment.*
+
--- a/38
+++ b/38
@ -0,0 +1,38 @@
				@@ -0,0 +1,38 @@
+application = json-search-server
+stack = stack
+hlint = hlint
+
+all: app docs
+
+build: app
+
+deps:
+	$(stack) build --only-dependencies
+
+app:
+	$(stack) build
+
+install:
+	$(stack) install
+
+docs:
+	$(stack) exec -- haddock --html --pretty-html src/*.hs app/Main.hs --hyperlinked-source --optghc=-DHADDOCK --odir=docs --show-all --use-unicode
+
+lint: hlint
+hlint:
+	$(hlint) .; :
+
+check:
+	$(stack) build --force-dirty --ghc-options="-Weverything"
+
+static:
+	$(stack) build --force-dirty --ghc-options="-optl-static -optc-static"
+
+exec:
+	$(stack) exec -- $(application) $(filter-out $@, $(MAKECMDGOALS))
+
+%:
+	@true
+
+.PHONY: build app docs all hlint static exec check install
+
--- a/README.md
+++ b/README.md
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				@@ -0,0 +1,326 @@
+# Json Search Server
+
+**v0.1.0**
+
+
+This application provides fuzzy search server for data stored in JSON format.
+
+
+The purpose of the development of this application was to use it with the website written on [Jekyll](https://jekyllrb.com/).
+
+---
+
+## License
+```
+Copyright (C) 2019, Maxim Lihachev, <envrm@yandex.ru>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <https://www.gnu.org/licenses/>.
+```
+
+# Algorithm
+
+The logic of this application is pretty simple:
+* All fields in the file are divided into separate words.
+* Each unique word in the search string is compared to the words in the file.
+* If the match is exact, the highest score is awarded.
+* If there is an inaccurate coincidence, the [Levenshtein distance](https://en.wikipedia.org/wiki/Levenshtein_distance) is calculated and the word score is formed on its basis.
+* Results are sorted in descending order of accuracy.
+
+
+# How to use
+
+## Build
+
+```
+$ make build
+or
+$ make static
+```
+
+There is [Vagrant](https://www.vagrantup.com/) file configured for starting Centos 7. This VM is used for making statically-linked binary file for target server.
+
+```
+host:~$ vagrant up
+host:~$ vagrant ssh
+
+vm:~$ cd /vagrant
+vm:~$ make static
+```
+
+Static executable file is in bin/ directory.
+
+## Run
+```
+$ make exec
+
+json-search-server v0.1.0: seach server for Json
+
+json-search-server [OPTIONS]
+
+Common flags:
+  -p    --port=3000              Search server port
+  -l    --logs=apache            apache | simple | json | disable | full
+  -c    --cached                 Store Json data into memory
+  -j -f --json=data.json --file  Json file name
+  -?    --help                   Display help message
+  -V    --version                Print version information
+        --numeric-version        Print just the version number
+```
+
+## Install
+
+```
+$ make install
+```
+
+
+# Requests
+
+## Get Server Settings
+
+```bash
+$ curl -sq http://localhost:3000/info
+
+{
+  "cached": false,
+  "logs": "full",
+  "file": "sample.json",
+  "port": 3000
+}
+```
+
+## Health Check
+
+```bash
+$ curl -sq http://localhost:3000/health
+
+{
+  "status": "ok",
+  "message": "2019-06-19 09:03:26.402385 UTC"
+}
+```
+
+```bash
+$ chmod a-r sample.json
+$ curl -sq http://localhost:3000/health
+
+{
+  "status": "fail",
+  "message": "2019-06-19 09:05:32.950256 UTC sample.json: openFile: permission denied (Permission denied)"
+}
+```
+
+## Search
+
+```bash
+$ curl -sq http://localhost:3000/search/article
+$ curl -sq http://localhost:3000/search?query=article
+
+[
+  [
+    {
+      "url": "/tags/foo.html",
+      "authors": "Author I, Author II",
+      "content": "This is article about Foo and Bar.",
+      "year": "1990",
+      "title": "Page one"
+    },
+    1,
+    -100
+  ]
+]
+```
+
+## Logs
+
+There are few formats for log messages. It is possible to disable logs completely passing argument `--log disable`.
+
+
+### --log apache (default)
+
+```bash
+127.0.0.1 - - [19/Jun/2019:12:14:16 +0300] "GET /info HTTP/1.1" 200 - "" "curl/7.54.0"
+127.0.0.1 - - [19/Jun/2019:12:14:18 +0300] "GET /health HTTP/1.1" 200 - "" "curl/7.54.0"
+```
+
+### --log simple
+
+```bash
+GET /health
+  Accept: */*
+  Status: 200 OK 0.00003s
+GET /info
+  Accept: */*
+  Status: 200 OK 0.000018s
+```
+
+### --log json
+
+```json
+{"time":"19/Jun/2019:12:20:06 +0300","response":{"status":200,"size":null,"body":null},"request":{"httpVersion":"1.1","path":"/health","size":0,"body":"","durationMs":7.0e-2,"remoteHost":{"hostAddress":"127.0.0.1","port":63436},"headers":[["Host","localhost:3000"],["User-Agent","curl/7.54.0"],["Accept","*/*"]],"queryString":[],"method":"GET"}}
+{"time":"19/Jun/2019:12:20:07 +0300","response":{"status":200,"size":null,"body":null},"request":{"httpVersion":"1.1","path":"/info","size":0,"body":"","durationMs":4.0e-2,"remoteHost":{"hostAddress":"127.0.0.1","port":63438},"headers":[["Host","localhost:3000"],["User-Agent","curl/7.54.0"],["Accept","*/*"]],"queryString":[],"method":"GET"}}
+```
+
+Or pretty-printed:
+
+```json
+{
+  "time": "19/Jun/2019:12:20:06 +0300",
+  "response": {
+    "status": 200,
+    "size": null,
+    "body": null
+  },
+  "request": {
+    "httpVersion": "1.1",
+    "path": "/health",
+    "size": 0,
+    "body": "",
+    "durationMs": 0.07,
+    "remoteHost": {
+      "hostAddress": "127.0.0.1",
+      "port": 63436
+    },
+    "headers": [
+      [
+        "Host",
+        "localhost:3000"
+      ],
+      [
+        "User-Agent",
+        "curl/7.54.0"
+      ],
+      [
+        "Accept",
+        "*/*"
+      ]
+    ],
+    "queryString": [],
+    "method": "GET"
+  }
+}
+```
+
+
+### --log full
+
+```bash
+"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
+"2019-06-19 09:05:22.226024 UTC"
+"------------------------------------------------------------------------------------------------------------------------"
+"Query: /health"
+"------------------------------------------------------------------------------------------------------------------------"
+Request
+    { requestMethod = "GET"
+    , httpVersion = HTTP/1.1
+    , rawPathInfo = "/health"
+    , rawQueryString = ""
+    , requestHeaders =
+        [
+            ( "Host"
+            , "localhost:3000"
+            )
+        ,
+            ( "User-Agent"
+            , "curl/7.54.0"
+            )
+        ,
+            ( "Accept"
+            , "*/*"
+            )
+        ]
+    , isSecure = False
+    , remoteHost = 127.0.0.1:63212
+    , pathInfo = [ "health" ]
+    , queryString = []
+    , requestBody = <IO ByteString>
+    , vault = <Vault>
+    , requestBodyLength = KnownLength 0
+    , requestHeaderHost = Just "localhost:3000"
+    , requestHeaderRange = Nothing
+    }
+```
+
+## Caching
+
+It is possible to store all data in RAM and use it even if the file is not readable.
+To do this, specify the argument `--cached`.
+
+
+# NGINX
+
+For using this service behind nginx web server might be used following configuration:
+
+```nginx
+upstream search_backend {
+        server 127.0.0.1:3000;
+}
+
+server {
+        listen 8080;
+        server_name search.server www.search.server;
+
+        # ...
+
+        location / {
+                add_header 'Access-Control-Allow-Origin' "$http_origin";
+                add_header 'Access-Control-Allow-Methods' 'GET, POST';
+                add_header 'Access-Control-Allow-Credentials' 'true';
+                add_header 'Access-Control-Allow-Headers' 'User-Agent,Keep-Alive,Content-Type';
+
+                proxy_set_header Host $host;
+                proxy_set_header X-Real-IP $remote_addr;
+                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+                proxy_set_header X-Forwarded-Host $remote_addr;
+                proxy_pass http://search_backend$uri?$args;
+        }
+
+		# This prevents intruders from obtaining information
+        # about the internal structure of the server. 
+        location /info {
+                proxy_pass http://search_backend/health;
+        }
+}
+```
+
+# Jekyll
+
+Creating a Json file using jekyll will look like this:
+
+```bash
+---
+layout: none
+search: none
+---
+
+{% assign all_pages = site.pages | where_exp: 'p', 'p.search != "none"' | where_exp: 'p', 'p.layout != "none"' %}
+
+[
+
+  {% for p in all_pages %}
+    {% capture all_authors %}{{ p.authors | join: ',' }}, {{ p.translators | join: ',' }}, {{ p.editors | join: ','  }}{% endcapture %}
+      {
+        "title": "{{ p.title | split: '<br />' | join: ' ' | xml_escape }}{% if p.tag %} «{{ p.tag }}» {% endif %}",
+        "authors": "{{ p.authors | join: ',' }}",
+        "persons": "{{ all_authors }}",
+        "content": {{ p.content | strip_html | jsonify }},
+        "tags": "{{ p.tags | join: ', ' }}",
+        "year": "{{ p.year }}",
+        "url": "{{ p.url | xml_escape }}"
+      }
+      {% unless forloop.last %},{% endunless %}
+  {% endfor %}
+
+]
+```
--- a/Setup.hs
+++ b/Setup.hs
@ -0,0 +1,2 @@
				@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
--- a/app/Main
+++ b/app/Main
--- a/app/Main.hs
+++ b/app/Main.hs
@ -0,0 +1,70 @@
				@@ -0,0 +1,70 @@
+{-# LANGUAGE NoImplicitPrelude   #-}
+{-# LANGUAGE Unsafe              #-}
+
+-- -----------------------------------------------------------------------------
+
+-- Copyright (C) 2019, Maxim Lihachev, <envrm@yandex.ru>
+
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+
+-- You should have received a copy of the GNU General Public License
+-- along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Json-search service
+--
+module Main (main) where
+
+import Relude                      ( Maybe (Nothing), Bool (False), IO, ($), id, null )
+
+import System.Exit                 ( die )
+import System.Environment          ( getArgs, withArgs )
+import System.Console.CmdArgs      ( cmdArgs, help, summary, typ, name, program, (&=) )
+
+import Text.Pretty.Simple          ( pPrint )
+
+import Server                      ( startServer, ServerSettings (ServerSettings, file, cached, logs, port), checkJsonFile )
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Default command line arguments
+--
+defaultSettings :: IO ServerSettings
+defaultSettings = cmdArgs
+                $ ServerSettings { port     = 3000          &= typ  "3000"        &= help "Search server port"
+                                 , logs     = "apache"      &= typ  "apache"      &= help "apache | simple | json | disable | full"
+                                 , cached   = False         &= typ  "False"       &= help "Store Json data into memory" &= name "cached"
+                                 , file     = Nothing       &= typ  "data.json"   &= help "Json file name" &= name "json"
+                                 } &= program "json-search-server"
+                                   &= summary "json-search-server v0.1.0: seach server for Json"
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Start application
+--
+main :: IO ()
+main = do
+      args <- getArgs
+      settings <- (if null args then withArgs ["--help"] else id) defaultSettings
+
+      pPrint settings
+
+      let fileStatus = checkJsonFile (file settings) in
+          case fileStatus of
+               "ok" ->
+                      startServer settings
+               _err ->
+                      die fileStatus
+
--- a/bin/json-search.x86_64.centos7
+++ b/bin/json-search.x86_64.centos7
--- a/package.yaml
+++ b/package.yaml
@ -0,0 +1,70 @@
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+name:                json-search-server
+version:             0.1.0.0
+# github:              ""
+license:             GPL-3.0-only
+author:              "Maxim Likhachev"
+maintainer:          "envrm@yandex.ru"
+copyright:           "2019 Maxim Likhachev"
+
+library:
+  source-dirs: src
+
+executables:
+  json-search-server:
+    main:         Main.hs
+    source-dirs:  app
+    dependencies: json-search-server
+
+extra-source-files:
+- README.md
+
+dependencies:
+- base
+- relude             ^>=0.4.0
+- cmdargs            ^>=0.10.20
+- aeson              ^>=1.4.0.0
+- edit-distance      ^>=0.2.2.1
+- text               ^>=1.2.3.1
+- time               ^>=1.8.0.2
+- uri-encode         ^>=1.5.0.5
+- scotty             ^>=0.11.4
+- wai                ^>=3.2.2
+- wai-extra          ^>=3.0.26
+- pretty-simple      ^>=2.2.0.1
+- MissingH           ^>=1.4.1.0
+- data-default-class ^>=0.1.2.0
+
+ghc-options:
+  - -fforce-recomp
+  - -fobject-code
+  - -O2
+  - -optc-O3
+  - -funfolding-use-threshold=16
+  - -threaded
+
+  - -Wincomplete-uni-patterns
+  - -Wincomplete-record-updates
+  - -Wmonomorphism-restriction
+  - -Wimplicit-prelude
+  - -Wmissing-local-signatures
+  - -Wmissing-exported-signatures
+  - -Wmissing-export-lists
+  - -Wmissing-import-lists
+  - -Wmissing-home-modules
+  - -Wmissing-methods
+  - -Wunused-packages
+  - -Wdodgy-imports
+  - -Widentities
+  - -Wredundant-constraints
+  - -Wpartial-fields
+  - -Wmissed-specialisations
+  - -Wcpp-undef
+  - -Wunused-imports
+  - -Wunused-matches
+
+  - -fno-cse
+  - -fhide-source-paths
+  - -freverse-errors
+
+  # - -Weverything
+
--- a/sample.json
+++ b/sample.json
@ -0,0 +1,29 @@
				@@ -0,0 +1,29 @@
+[
+  {
+    "title": "Page one",
+    "authors": "Author I, Author II",
+    "persons": "Editor, Translator",
+    "content": "This is article about Foo and Bar.",
+    "tags": "foo, bar",
+    "year": "1990",
+    "url": "/pages/foo.html"
+  },
+  {
+    "title": "Page two",
+    "authors": "Author III",
+    "persons": "",
+    "content": "Sample page.",
+    "tags": "bar, baz",
+    "year": "2000",
+    "url": "/pages/bar.html"
+  },
+  {
+    "title": "Page three",
+    "authors": "Author IV",
+    "persons": "Translator",
+    "content": "",
+    "tags": "baz",
+    "year": "2010",
+    "url": "/pages/baz.html"
+  }
+]
--- a/src/Search.hs
+++ b/src/Search.hs
@ -0,0 +1,243 @@
				@@ -0,0 +1,243 @@
+{-# LANGUAGE NoImplicitPrelude     #-}
+{-# LANGUAGE DeriveGeneric         #-}
+{-# LANGUAGE OverloadedStrings     #-}
+{-# LANGUAGE PatternSynonyms       #-}
+{-# LANGUAGE ViewPatterns          #-}
+{-# LANGUAGE TransformListComp     #-}
+{-# LANGUAGE Unsafe                #-}
+
+-- -----------------------------------------------------------------------------
+
+-- Copyright (C) 2019, Maxim Lihachev, <envrm@yandex.ru>
+
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+
+-- You should have received a copy of the GNU General Public License
+-- along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Fuzzy search for JSON data
+--
+module Search (Json, tokenize, findJsonObjects) where
+
+-- -----------------------------------------------------------------------------
+
+import Relude   ( Maybe (Just, Nothing), Bool, Int, String, Text
+                , otherwise, sortWith, toString, toText, div
+                , (-), (*), ($), (&), (<$>), (==), (<>), (<), (>), (>=), (&&), (.) )
+
+import Data.Aeson        ( FromJSON, ToJSON, toJSON, object, (.=) )
+import Data.Char         ( toLower, isAlphaNum )
+import Data.List         ( minimum, map, sum, elem, filter, length, nub )
+import GHC.Generics      ( Generic )
+import Text.EditDistance ( levenshteinDistance, defaultEditCosts )
+
+import qualified Data.Text as T            ( map, length, take, toLower, strip, words )
+import qualified Network.URI.Encode as URI ( decodeText )
+
+import Settings ( maxContentLength, minPatternLength
+                , outOfScore, fullScore, scoreMultiplier, replaceChar )
+
+-- -----------------------------------------------------------------------------
+
+pattern T :: String -> Text
+pattern T str <- (toString -> str)
+  where T = toText
+
+data FindStrictness = Strict -- ^ Exact match
+                    | Fuzzy  -- ^ Fuzzy search
+
+-- | Структура 'Score'
+data Score = Score { matches :: !Int -- ^ Count of matches
+                   , diffs   :: !Int -- ^ Count of differences (errors) or 'fullScore'
+                   }
+
+--
+-- | Json format:
+--
+--    [
+--      {
+--        "title": "Page one",
+--        "authors": "Author I, Author II",
+--        "persons": "Editor, Translator",
+--        "content": "This is article about Foo and Bar.",
+--        "tags": "foo, bar",
+--        "year": "1990",
+--        "url": "/pages/foo.html"
+--      },
+--      {...}
+--    ]
+--
+data Json = Json { title    :: !Text
+                 , authors  :: !Text
+                 , persons  :: !Text
+                 , content  :: !Text
+                 , tags     :: !Text
+                 , year     :: !Text
+                 , url      :: !Text } deriving (Generic)
+
+instance FromJSON Json
+
+--
+-- | Json output preprocessing
+--
+-- * URLs are decoded.
+-- * "content" is shortened.
+--
+instance ToJSON Json where
+    toJSON jsonObject =
+        object [ "title"    .= title    jsonObject
+               , "authors"  .= authors  jsonObject
+               , "year"     .= year     jsonObject
+               , "url"      .= (url     jsonObject & URI.decodeText)
+               , "content"  .= (content jsonObject & shortenWith "..." maxContentLength) ]
+               -- "tags"    .= (tags    jsonObject & shortenWith "..." maxContentLength) ]
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Shorten text to specified length and append a given suffix.
+--
+-- >>> shortenWith "" 8 "1234567890"
+-- "12345678"
+--
+-- >>> shortenWith "..." 8 "1234567890"
+-- "12345..."
+--
+shortenWith :: Text -> Int -> Text -> Text
+shortenWith suffix n string | T.length string >= n = T.strip (T.take (n - T.length suffix) string) <> suffix
+                            | otherwise = string
+
+--
+-- |
+--
+valid :: Score -> Bool
+valid (Score  x y) = x > 0 && y < 0
+
+-- |
+sumall :: (a -> Int) -> [a] -> Int
+sumall fn = sum . map fn
+
+--
+-- | Calculation of relevance:
+--
+-- * For each complete match with the template (score == 0),
+--   'fullScore' points are given (100 by default),
+--   the remaining points are added together.
+--
+-- * Result with a minus is used for
+--   correct sorting by decreasing accuracy of results.
+--
+-- >>> getScore [Score { matches = 1, diffs = 0 }, Score { matches = 2, diffs = 1 }]
+-- "-1020"
+--
+getScore :: [Score] -> Int
+getScore = sumall scores
+    where scores (Score x 0) = fullScore * x
+          scores (Score x s) = -x * scoreMultiplier `div` s
+
+--
+-- | Splitting text into separate words.
+--
+-- * Keeping only alpha-num characters.
+-- * Deleting words shorter than 'minPatternLength'.
+--
+-- >>> tokenize "an alpha, a beta: a gam-ma; and a (delta)"
+-- ["alpha", "beta", "gam", "ma", "delta"]
+--
+tokenize :: Text -> [Text]
+tokenize xs = filter (\w -> T.length w >= minPatternLength) wds
+  where wds = T.words $ T.map isChar xs
+        isChar ch | isAlphaNum ch = replaceChar . toLower $ ch
+                  | otherwise = ' '
+
+-- | [Levenshtein distance](https://en.wikipedia.org/wiki/Levenshtein_distance) computing
+levenshtein :: Text -> Text -> Int
+levenshtein str txt = levenshteinDistance defaultEditCosts (toString str) (toString txt)
+
+--
+-- | Comparing a word with all the words of a text
+--   and returning the 'Score'.
+--
+findWord :: [Text] -> Text -> Score
+findWord txt word | word `elem` txt = Score { matches = 1,   diffs = 0 }
+                  | otherwise  = Score { matches = lns, diffs = ms }
+    where ls  = [ l | wd <- txt, let l = levenshtein word wd, l < outOfScore ]
+          lns = length ls
+          ms  | lns > 0   = minimum ls
+              | otherwise = outOfScore
+
+--
+-- | Evaluation of the sameness of two strings.
+--
+-- >>> locate "string" "string" Strict
+-- Score 1 -1000       -- exact match without any errors
+--
+-- >>> locate "string" "strings" Fuzzy
+-- Score 1 -10         -- match without one difference
+--
+-- >>> locate "string" "text" Fuzzy
+-- Score 0 outOfScore  -- string not found
+--
+locate :: Text -> Text -> FindStrictness -> Score
+-- Empty string or empty text
+locate (T[])  _   _   = Score { matches = 0, diffs = outOfScore }
+locate _   (T[])  _   = Score { matches = 0, diffs = outOfScore }
+-- Strict search
+locate str txt Strict | T.toLower str ==  T.toLower txt = Score { matches = 1, diffs = fullScore }
+                       | otherwise                      = Score { matches = 0, diffs = outOfScore }
+-- Fuzzy search
+locate str txt Fuzzy  = Score { matches = sumall matches trs, diffs = getScore trs }
+                where trs = findWord wds <$> sxs
+                      wds = tokenize txt
+                      sxs = nub $ tokenize str
+
+--
+-- | Alias for 'collision'.
+--
+-- >>> "string" ==~ "Text with string"
+-- Score 1 fullScore
+--
+(==~) = locate
+
+--
+-- | Compare all file fields with a string.
+--
+anyMatch :: Text -> Json -> Score
+anyMatch string jsonObject = Score { matches = length l, diffs = sumall diffs l }
+             where l = filter valid [ string ==~ fullname            $ Fuzzy,
+                                      string ==~ content jsonObject  $ Fuzzy,
+                                      string ==~ year jsonObject     $ Strict,
+                                      string ==~ tags jsonObject     $ Fuzzy
+                                    ]
+                   fullname  = persons jsonObject <> " " <> title jsonObject
+--
+-- | Alias for 'anyMatch'.
+--
+-- >>> "string" `within` Json
+--
+within = anyMatch
+
+--
+-- | Search for Json objects which include passing string.
+--
+findJsonObjects :: Maybe [Json] -> Text -> [(Json, Int, Int)]
+findJsonObjects Nothing _          = []
+findJsonObjects (Just objs) string | T.length string < minPatternLength = []
+                                   | otherwise = foundPages
+    where foundPages = [ (obj, mcs, dfs) | obj <- objs,
+                                         let item = string `within` obj, valid item,
+                                         let mcs  = matches item,
+                                         let dfs  = diffs item,
+                                         then sortWith by dfs]
+
--- a/src/Server.hs
+++ b/src/Server.hs
@ -0,0 +1,201 @@
				@@ -0,0 +1,201 @@
+{-# LANGUAGE NoImplicitPrelude     #-}
+{-# LANGUAGE DeriveAnyClass        #-}
+{-# LANGUAGE DeriveGeneric         #-}
+{-# LANGUAGE DeriveDataTypeable    #-}
+{-# LANGUAGE OverloadedStrings     #-}
+{-# LANGUAGE ScopedTypeVariables   #-}
+{-# LANGUAGE Unsafe                #-}
+
+-- -----------------------------------------------------------------------------
+
+-- Copyright (C) 2019, Maxim Lihachev, <envrm@yandex.ru>
+
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+
+-- You should have received a copy of the GNU General Public License
+-- along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Scotty-based web service which provides API for "Search" module.
+--
+module Server (startServer, ServerSettings (..), checkHealth, checkJsonFile) where
+
+
+import Relude                                      ( Maybe (Just, Nothing), String, Text, Int, Bool, IO, Show
+                                                   , ($), (.), (>>), (=<<), (>>=), (<>)
+                                                   , otherwise, liftIO, show, return, replicate )
+
+import Data.Aeson                                  ( ToJSON, decodeFileStrict' )
+import Web.Scotty                                  ( ActionM, scotty, get, json, notFound, param, middleware, redirect )
+import Network.Wai                                 ( Middleware, Application, Request, Response, ResponseReceived, rawQueryString, rawPathInfo )
+import Network.Wai.Middleware.RequestLogger.JSON   ( formatAsJSON )
+import Network.Wai.Middleware.RequestLogger        ( logStdout, logStdoutDev, mkRequestLogger, outputFormat
+                                                   , OutputFormat (CustomOutputFormat, CustomOutputFormatWithDetails) )
+
+import Text.Pretty.Simple                          ( pPrint )
+import Foreign.Marshal.Unsafe                      ( unsafeLocalState )
+import GHC.Generics                                ( Generic )
+import Data.Default.Class                          ( Default (def) )
+
+import System.Console.CmdArgs                      ( Data )
+import System.IO                                   ( openFile, hClose, IOMode (ReadMode) )
+import Control.Exception                           ( handle, IOException )
+import Control.Monad                               ( join )
+import Data.Time                                   ( getCurrentTime, UTCTime )
+import Data.Text.Encoding                          ( decodeUtf8 )
+import Network.URI.Encode                          ( decodeText )
+
+import Search                                      ( findJsonObjects, Json )
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Server settings' format.
+--
+data ServerSettings = ServerSettings { port    :: Int
+                                     , logs    :: String
+                                     , cached  :: Bool
+                                     , file    :: Maybe String
+                                     } deriving (Show, Data, Generic, ToJSON)
+
+--
+-- | Healthcheck's format.
+--
+data Health = Health { status  :: !String
+                     , message :: !String } deriving (Show, Generic, ToJSON)
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | If 'filename' is readable then "ok" or error message in other case.
+--
+checkJsonFile :: Maybe String  -> String
+checkJsonFile Nothing         = "ERROR: Data file is not specified"
+checkJsonFile (Just filename) = unsafeLocalState
+                              $ handle (\ (e :: IOException) -> return $ show e)
+                              $ openFile filename ReadMode >>= hClose >> return "ok"
+
+--
+-- | Service checking.
+--
+-- If file is exists and readable return "ok".
+--
+-- >>> curl json-search-server:port/health
+-- {
+--   "status":"ok",
+--   "message":""
+-- }
+--
+-- Otherwise return "warning" (if cache is used) or "fail" status with error message.
+--
+-- >>> curl json-search-server:port/health
+-- {
+--   "status":"fail",
+--   "message":"broken.json: openFile: does not exist (No such file or directory)"
+-- }
+--
+checkHealth :: UTCTime -> Bool -> Maybe String -> IO (ActionM ())
+checkHealth serverStartTime withCache filename =
+    let currentStatus = checkJsonFile filename in do
+      time <- getCurrentTime
+
+      return $ json $ case currentStatus of
+        "ok" ->
+                if withCache
+                   then Health "ok" ("cache was loaded " <> show serverStartTime)
+                   else Health "ok" (show time)
+        _err ->
+                if withCache
+                   then Health ("warning: using cache from " <> show serverStartTime) currentStatus
+                   else Health "fail" (show time <> " " <> currentStatus)
+
+--
+-- | Read JSON data from file.
+--
+-- NOINLINE pragma uses to force read file each function call.
+--
+loadJSON :: Maybe String -> Maybe [Json]
+loadJSON Nothing         = Nothing
+loadJSON (Just filename) = unsafeLocalState $ decodeFileStrict' filename
+{-# NOINLINE loadJSON #-}
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Run a search with or without cache.
+--
+-- If argument --cached was passed, it uses the stored data.
+-- In another case, re-reads the data from the file.
+--
+findWithCache :: Maybe [Json] -> Maybe String -> Text -> [(Json, Int, Int)]
+findWithCache Nothing filename string = findJsonObjects (loadJSON filename) string
+findWithCache cache   _        string = findJsonObjects cache string
+
+--
+-- | Format or omit all Middleware output.
+--
+formatLog :: String -> IO Middleware
+formatLog "json" = mkRequestLogger def { outputFormat = CustomOutputFormatWithDetails formatAsJSON }
+formatLog _none  = mkRequestLogger def { outputFormat = CustomOutputFormat (\_ _ _ _ -> "") }
+
+--
+-- | Log types.
+--
+logRequest :: String -> Application -> Request -> (Response -> IO ResponseReceived) -> IO ResponseReceived
+logRequest format app req respond =
+  let ret f = f app req respond
+      header = replicate 120
+  in
+      case format of
+          "full"    -> do
+                        pPrint $ header '~'
+                        pPrint . show =<< getCurrentTime
+                        pPrint $ header '-'
+                        pPrint $ "Query: "
+                                 <> (decodeText . decodeUtf8 $ rawPathInfo req)
+                                 <> (decodeText . decodeUtf8 $ rawQueryString req)
+                        pPrint $ header '-'
+                        pPrint req
+
+                        ret =<< formatLog "none"
+
+          "disable" -> ret =<< formatLog "none"
+
+          "json"    -> ret =<< formatLog "json"
+
+          "simple"  -> ret logStdoutDev
+
+          _apache   -> ret logStdout
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Start Scotty server with passing 'ServerSettings'.
+--
+startServer :: ServerSettings -> IO ()
+startServer settings@(ServerSettings serverPort logFormat withCache filename) =
+    let cache | withCache = loadJSON filename
+              | otherwise = Nothing
+    in do
+        serverStartTime <- getCurrentTime
+
+        scotty serverPort $ do
+            middleware $ logRequest logFormat
+
+            get "/info"          $ json settings
+            get "/health"        $ join $ liftIO $ checkHealth serverStartTime withCache filename
+            get "/search"        $ json . findWithCache cache filename =<< param "query"
+            get "/search/:query" $ json . findWithCache cache filename =<< param "query"
+
+            notFound             $ redirect "/info"
+
--- a/src/Settings.hs
+++ b/src/Settings.hs
@ -0,0 +1,66 @@
				@@ -0,0 +1,66 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+{-# LANGUAGE Safe              #-}
+
+-- -----------------------------------------------------------------------------
+
+-- Copyright (C) 2019, Maxim Lihachev, <envrm@yandex.ru>
+
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+-- GNU General Public License for more details.
+
+-- You should have received a copy of the GNU General Public License
+-- along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+-- -----------------------------------------------------------------------------
+
+--
+-- | Fuzzy search settings.
+--
+module Settings ( maxContentLength
+                , minPatternLength
+                , scoreMultiplier
+                , outOfScore
+                , fullScore
+                , replaceChar )
+where
+
+import Relude ( Int, Char, (+), (*) )
+
+-- -----------------------------------------------------------------------------
+
+-- | Maximum length of strings in resulting json.
+maxContentLength :: Int
+maxContentLength = 160
+
+-- | Minimum length of search pattern.
+minPatternLength :: Int
+minPatternLength = 4
+
+-- | Maximum count of differencies between the search words and the string.
+maxVariation :: Int
+maxVariation = 2
+
+-- | Awarded for insufficient string matching.
+outOfScore :: Int
+outOfScore = maxVariation + 1
+
+-- | Awarded with the full concurrence with the string.
+fullScore :: Int
+fullScore = -10 * scoreMultiplier
+
+-- | The larger the number, the more accurate the sorting by relevance.
+scoreMultiplier :: Int
+scoreMultiplier = 10
+
+-- | List of characters to replace during text preprocessing.
+replaceChar :: Char -> Char
+replaceChar 'ё' = 'е'
+replaceChar ch  = ch
+
--- a/stack.yaml
+++ b/stack.yaml
@ -0,0 +1,64 @@
				@@ -0,0 +1,64 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-13.23
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#  subdirs:
+#  - auto-update
+#  - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
+# (e.g., acme-missiles-0.3)
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=1.9"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor