diff --git a/nifi-commons/nifi-expression-language/pom.xml b/nifi-commons/nifi-expression-language/pom.xml index da6d7d8334..f4ea10b7a8 100644 --- a/nifi-commons/nifi-expression-language/pom.xml +++ b/nifi-commons/nifi-expression-language/pom.xml @@ -61,5 +61,13 @@ hamcrest-all provided + + com.jayway.jsonpath + json-path + + + com.fasterxml.jackson.core + jackson-databind + diff --git a/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionLexer.g b/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionLexer.g index 1b3c345817..37cb02a2a7 100644 --- a/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionLexer.g +++ b/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionLexer.g @@ -152,6 +152,7 @@ OR : 'or'; AND : 'and'; JOIN : 'join'; TO_LITERAL : 'literal'; +JSON_PATH : 'jsonPath'; // 2 arg functions SUBSTRING : 'substring'; diff --git a/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionParser.g b/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionParser.g index 5e0c4932d2..726246d3c1 100644 --- a/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionParser.g +++ b/nifi-commons/nifi-expression-language/src/main/antlr3/org/apache/nifi/attribute/expression/language/antlr/AttributeExpressionParser.g @@ -75,7 +75,7 @@ tokens { // functions that return Strings zeroArgString : (TO_UPPER | TO_LOWER | TRIM | TO_STRING | URL_ENCODE | URL_DECODE) LPAREN! RPAREN!; oneArgString : ((SUBSTRING_BEFORE | SUBSTRING_BEFORE_LAST | SUBSTRING_AFTER | SUBSTRING_AFTER_LAST | REPLACE_NULL | REPLACE_EMPTY | - PREPEND | APPEND | FORMAT | STARTS_WITH | ENDS_WITH | CONTAINS | JOIN) LPAREN! anyArg RPAREN!) | + PREPEND | APPEND | FORMAT | STARTS_WITH | ENDS_WITH | CONTAINS | JOIN | JSON_PATH) LPAREN! anyArg RPAREN!) | (TO_RADIX LPAREN! anyArg (COMMA! anyArg)? RPAREN!); twoArgString : ((REPLACE | REPLACE_FIRST | REPLACE_ALL) LPAREN! anyArg COMMA! anyArg RPAREN!) | (SUBSTRING LPAREN! anyArg (COMMA! anyArg)? RPAREN!); diff --git a/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/Query.java b/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/Query.java index 4476097754..9bd653a3a9 100644 --- a/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/Query.java +++ b/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/Query.java @@ -59,6 +59,7 @@ import org.apache.nifi.attribute.expression.language.evaluation.functions.InEval import org.apache.nifi.attribute.expression.language.evaluation.functions.IndexOfEvaluator; import org.apache.nifi.attribute.expression.language.evaluation.functions.IsEmptyEvaluator; import org.apache.nifi.attribute.expression.language.evaluation.functions.IsNullEvaluator; +import org.apache.nifi.attribute.expression.language.evaluation.functions.JsonPathEvaluator; import org.apache.nifi.attribute.expression.language.evaluation.functions.LastIndexOfEvaluator; import org.apache.nifi.attribute.expression.language.evaluation.functions.LengthEvaluator; import org.apache.nifi.attribute.expression.language.evaluation.functions.LessThanEvaluator; @@ -152,6 +153,7 @@ import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpre import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.IS_EMPTY; import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.IS_NULL; import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.JOIN; +import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.JSON_PATH; import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.LAST_INDEX_OF; import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.LENGTH; import static org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser.LESS_THAN; @@ -1352,9 +1354,15 @@ public class Query { "getDelimitedField"); } } - default: - throw new AttributeExpressionLanguageParsingException("Expected a Function-type expression but got " + tree.toString()); - } + case JSON_PATH: { + verifyArgCount(argEvaluators, 1, "jsonPath"); + return addToken(new JsonPathEvaluator(toStringEvaluator(subjectEvaluator), + toStringEvaluator(argEvaluators.get(0), "first argument to jsonPath")), "jsonPath"); + } + default: + throw new AttributeExpressionLanguageParsingException( + "Expected a Function-type expression but got " + tree.toString()); + } } public static class Range { diff --git a/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/evaluation/functions/JsonPathEvaluator.java b/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/evaluation/functions/JsonPathEvaluator.java new file mode 100644 index 0000000000..0ef39d1141 --- /dev/null +++ b/nifi-commons/nifi-expression-language/src/main/java/org/apache/nifi/attribute/expression/language/evaluation/functions/JsonPathEvaluator.java @@ -0,0 +1,127 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.nifi.attribute.expression.language.evaluation.functions; + +import java.util.List; +import java.util.Map; +import java.util.Objects; + +import org.apache.nifi.attribute.expression.language.evaluation.Evaluator; +import org.apache.nifi.attribute.expression.language.evaluation.QueryResult; +import org.apache.nifi.attribute.expression.language.evaluation.StringEvaluator; +import org.apache.nifi.attribute.expression.language.evaluation.StringQueryResult; +import org.apache.nifi.attribute.expression.language.evaluation.literals.StringLiteralEvaluator; +import org.apache.nifi.attribute.expression.language.exception.AttributeExpressionLanguageException; + +import com.jayway.jsonpath.Configuration; +import com.jayway.jsonpath.DocumentContext; +import com.jayway.jsonpath.InvalidJsonException; +import com.jayway.jsonpath.JsonPath; +import com.jayway.jsonpath.spi.json.JacksonJsonProvider; +import com.jayway.jsonpath.spi.json.JsonProvider; + + +public class JsonPathEvaluator extends StringEvaluator { + + private static final StringQueryResult EMPTY_RESULT = new StringQueryResult(""); + private static final Configuration STRICT_PROVIDER_CONFIGURATION = Configuration.builder().jsonProvider(new JacksonJsonProvider()).build(); + private static final JsonProvider JSON_PROVIDER = STRICT_PROVIDER_CONFIGURATION.jsonProvider(); + + private final Evaluator subject; + private final Evaluator jsonPathExp; + private final JsonPath precompiledJsonPathExp; + + public JsonPathEvaluator(final Evaluator subject, final Evaluator jsonPathExp) { + this.subject = subject; + this.jsonPathExp = jsonPathExp; + // if the search string is a literal, we don't need to evaluate it each + // time; we can just + // pre-compile it. Otherwise, it must be compiled every time. + if (jsonPathExp instanceof StringLiteralEvaluator) { + precompiledJsonPathExp = compileJsonPathExpression(jsonPathExp.evaluate(null).getValue()); + } else { + precompiledJsonPathExp = null; + } + + } + + @Override + public QueryResult evaluate(final Map attributes) { + final String subjectValue = subject.evaluate(attributes).getValue(); + if (subjectValue == null || subjectValue.length() == 0) { + throw new AttributeExpressionLanguageException("Subject is empty"); + } + DocumentContext documentContext = null; + try { + documentContext = validateAndEstablishJsonContext(subjectValue); + } catch (InvalidJsonException e) { + throw new AttributeExpressionLanguageException("Subject contains invalid JSON: " + subjectValue, e); + } + + final JsonPath compiledJsonPath; + if (precompiledJsonPathExp != null) { + compiledJsonPath = precompiledJsonPathExp; + } else { + compiledJsonPath = compileJsonPathExpression(jsonPathExp.evaluate(attributes).getValue()); + } + + Object result = null; + try { + result = documentContext.read(compiledJsonPath); + } catch (Exception e) { + // assume the path did not match anything in the document + return EMPTY_RESULT; + } + + return new StringQueryResult(getResultRepresentation(result, EMPTY_RESULT.getValue())); + } + + + @Override + public Evaluator getSubjectEvaluator() { + return subject; + } + + static DocumentContext validateAndEstablishJsonContext(final String json) { + final DocumentContext ctx = JsonPath.using(STRICT_PROVIDER_CONFIGURATION).parse(json); + return ctx; + } + + static boolean isJsonScalar(final Object obj) { + return !(obj instanceof Map || obj instanceof List); + } + + static String getResultRepresentation(final Object jsonPathResult, final String defaultValue) { + if (isJsonScalar(jsonPathResult)) { + return Objects.toString(jsonPathResult, defaultValue); + } else if (jsonPathResult instanceof List && ((List) jsonPathResult).size() == 1) { + return getResultRepresentation(((List) jsonPathResult).get(0), defaultValue); + } else { + return JSON_PROVIDER.toJson(jsonPathResult); + } + } + + static JsonPath compileJsonPathExpression(String exp) { + try { + return JsonPath.compile(exp); + } catch (Exception e) { + throw new AttributeExpressionLanguageException("Invalid JSON Path expression: " + exp, e); + } + } + +} + diff --git a/nifi-commons/nifi-expression-language/src/test/java/org/apache/nifi/attribute/expression/language/TestQuery.java b/nifi-commons/nifi-expression-language/src/test/java/org/apache/nifi/attribute/expression/language/TestQuery.java index cee4ccaa1a..39622cb649 100644 --- a/nifi-commons/nifi-expression-language/src/test/java/org/apache/nifi/attribute/expression/language/TestQuery.java +++ b/nifi-commons/nifi-expression-language/src/test/java/org/apache/nifi/attribute/expression/language/TestQuery.java @@ -22,6 +22,10 @@ import static org.junit.Assert.assertTrue; import static org.hamcrest.Matchers.greaterThan; import static org.hamcrest.MatcherAssert.assertThat; +import java.io.BufferedInputStream; +import java.io.IOException; +import java.io.InputStreamReader; +import java.io.Reader; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Collections; @@ -236,6 +240,34 @@ public class TestQuery { assertEquals("true", Query.evaluateExpressions("${x:equals(\"${a}\")}", attributes, null)); } + @Test + public void testJsonPath() { + final Map attributes = new HashMap<>(); + attributes.put("json", getResourceAsString("/json/address-book.json")); + verifyEquals("${json:jsonPath('$.firstName')}", attributes, "John"); + verifyEquals("${json:jsonPath('$.address.postalCode')}", attributes, "10021-3100"); + verifyEquals("${json:jsonPath(\"$.phoneNumbers[?(@.type=='home')].number\")}", attributes, "212 555-1234"); + verifyEquals("${json:jsonPath('$.phoneNumbers')}", attributes, + "[{\"type\":\"home\",\"number\":\"212 555-1234\"},{\"type\":\"office\",\"number\":\"646 555-4567\"}]"); + verifyEquals("${json:jsonPath('$.missing-path')}", attributes, ""); + try { + verifyEquals("${json:jsonPath('$..')}", attributes, ""); + Assert.fail("Did not detect bad JSON path expression"); + } catch (final AttributeExpressionLanguageException e) { + } + try { + verifyEquals("${missing:jsonPath('$.firstName')}", attributes, ""); + Assert.fail("Did not detect empty JSON document"); + } catch (AttributeExpressionLanguageException e) { + } + attributes.put("invalid", "[}"); + try { + verifyEquals("${invlaid:jsonPath('$.firstName')}", attributes, "John"); + Assert.fail("Did not detect invalid JSON document"); + } catch (AttributeExpressionLanguageException e) { + } + } + @Test public void testJoin() { final Map attributes = new HashMap<>(); @@ -1282,4 +1314,25 @@ public class TestQuery { assertEquals(expectedResult, result.getValue()); } + + private String getResourceAsString(String resourceName) { + Reader reader = new InputStreamReader(new BufferedInputStream(getClass().getResourceAsStream(resourceName))); + int n = 0; + char[] buf = new char[1024]; + StringBuilder sb = new StringBuilder(); + while (n != -1) { + try { + n = reader.read(buf, 0, buf.length); + } catch (IOException e) { + throw new RuntimeException("failed to read resource", e); + } + if (n > 0) { + sb.append(buf, 0, n); + } + } + return sb.toString(); + + + } + } diff --git a/nifi-commons/nifi-expression-language/src/test/resources/json/address-book.json b/nifi-commons/nifi-expression-language/src/test/resources/json/address-book.json new file mode 100644 index 0000000000..3348bc36fb --- /dev/null +++ b/nifi-commons/nifi-expression-language/src/test/resources/json/address-book.json @@ -0,0 +1,19 @@ +{ + "firstName": "John", "lastName": "Smith", "age": 25, + "address" : { + "streetAddress": "21 2nd Street", + "city": "New York", + "state": "NY", + "postalCode": "10021-3100" + }, + "phoneNumbers": [ + { + "type": "home", + "number": "212 555-1234" + }, + { + "type": "office", + "number": "646 555-4567" + } + ] + } \ No newline at end of file diff --git a/nifi-docs/src/main/asciidoc/expression-language-guide.adoc b/nifi-docs/src/main/asciidoc/expression-language-guide.adoc index 9c08ef445e..1a327c842c 100644 --- a/nifi-docs/src/main/asciidoc/expression-language-guide.adoc +++ b/nifi-docs/src/main/asciidoc/expression-language-guide.adoc @@ -1215,7 +1215,63 @@ Expressions will provide the following results: |======================================================================================= +[.function] +=== jsonPath +*Description*: [.description]#The `jsonPath` function generates a string by evaluating the Subject as JSON and applying a JSON + path expression. An empty string is generated if the Subject does not contain valid JSON, the _jsonPath_ is invalid, or the path + does not exist in the Subject. If the evaluation results in a scalar value, the string representation of scalar value is + generated. Otherwise a string representation of the JSON result is generated. A JSON array of length 1 is special cased + when `[0]` is a scalar, the string representation of `[0]` is generated.^1^# + +*Subject Type*: [.subject]#String# + +*Arguments*: + [.argName]#_jsonPath_# : [.argDesc]#the JSON path expression used to evaluate the Subject.# + +*Return Type*: [.returnType]#String# + +*Examples*: If the "myJson" attribute is + +.......... +{ + "firstName": "John", + "lastName": "Smith", + "isAlive": true, + "age": 25, + "address": { + "streetAddress": "21 2nd Street", + "city": "New York", + "state": "NY", + "postalCode": "10021-3100" + }, + "phoneNumbers": [ + { + "type": "home", + "number": "212 555-1234" + }, + { + "type": "office", + "number": "646 555-4567" + } + ], + "children": [], + "spouse": null +} +.......... + +.jsonPath Examples +|=================================================================== +| Expression | Value +| `${myJson:jsonPath('$.firstName')}` | `John` +| `${myJson:jsonPath('$.address.postalCode')}` | `10021-3100` +| `${myJson:jsonPath('$.phoneNumbers[?(@.type=="home")].number')}`^1^ | `212 555-1234` +| `${myJson:jsonPath('$.phoneNumbers')}` | `[{"type":"home","number":"212 555-1234"},{"type":"office","number":"646 555-4567"}]` +| `${myJson:jsonPath('$.missing-path')}` | _empty_ +| `${myJson:jsonPath('$.bad-json-path..')}` | _exception bulletin_ +|=================================================================== + +An empty subject value or a subject value with an invalid JSON document results in an exception bulletin. [[numbers]] == Mathematical Operations and Numeric Manipulation