While attempting to create a load test for a client, a post request to a critical endpoint failed due to JMeter converting "\\\" to "\\" in the post's body data. After the conversion, JMeter sends an invalid JSON to the server and it responds with 400 Bad Request. The client has a really weird (bad) endpoint where it accepts json in json in json which seems to throw off JMeter parser. Body Data in HTTP Request (POST): {"order":"{\"id\":0,\"order_date\":\"3/8/2019\",\"order_data\":{\"items\":[{\"id\":1876318,\"quantity\":1,\"name\":\"Air Filter\",\"price\":8.54,\"retail_price\":8.54,\"msrp\":0.0,\"price_level\":{\"price_level_id\":1,\"price_level\":\"RETAIL\",\"retail_multipler\":1.00,\"description\":\"Regular retail\",\"price_type\":{\"price_type_id\":1,\"price_type\":\"Regular\",\"label\":\"\"}},\"is_hazmat\":false,\"is_accessory\":false,\"oversize_category_id\":null,\"oem_number\":\"W10311524\",\"image_url\":\"https://www.redacted.com/dbImages/i/00004039/Air-Filter-W10311524-01215703.jpg\",\"quantity_by_dc\":[{\"id\":1,\"quantity\":0},{\"id\":2,\"quantity\":0}],\"repair_time\":null,\"repair_savings\":null,\"skill_level\":1,\"labor_hours\":null,\"prodcut_categories\":[{\"id\":1,\"name\":\"Appliances\"}]}],\"email\":\"${email}\",\"billing_address\":{\"first_name\":\"${first_name}\",\"last_name\":\"${last_name}\",\"street1\":\"2600 S River Rd\",\"street2\":\"\",\"city\":\"Des Plaines\",\"state\":\"IL\",\"country\":\"US\",\"zipcode\":\"60018\",\"phone\":\"1231231234\",\"ext\":\"\",\"business_name\":\"\",\"is_business_address\":false,\"is_po_box\":false},\"shipping_address\":{\"first_name\":\"${first_name}\",\"last_name\":\"${last_name}\",\"street1\":\"2600 S River Rd\",\"street2\":\"\",\"city\":\"Des Plaines\",\"state\":\"IL\",\"country\":\"US\",\"zipcode\":\"60018\",\"phone\":\"1231231234\",\"ext\":\"\",\"business_name\":\"\",\"is_business_address\":false,\"is_po_box\":false},\"shipping_choice\":{\"shipping_option_id\":1,\"ship_to_po_box\":false,\"is_saturday_delivery\":false,\"ship_complete\":true,\"is_home_business\":false},\"total\":15.71,\"discount\":0.0,\"subtotal\":8.54,\"shipping_charge\":6.25,\"offshore_surcharge\":0.0,\"saturday_shipping_surcharge\":0.0,\"saturday_shipping_surcharge_for_ship_method\":15.00,\"oversize_surcharge\":0.0,\"weight_surcharge\":0.0,\"international_processing_fee\":0.0,\"sales_tax\":0.92,\"sales_tax_label\":\"Estimated Sales Tax\",\"purchase_order_number\":null,\"promotion_code\":\"\",\"device_data\":\"{\\\"device_session_id\\\":\\\"${sessionId}\\\",\\\"fraud_merchant_id\\\":\\\"600000\\\"}\",\"is_promo_code_valid\":false},\"sop_number\":\"\",\"security_code\":null,\"rc_order_form\":\"\",\"o_checksum\":\"${o_checksum}\",\"rc_checksum\":\"${rc_checksum}\"}","payment":{"payment_type_id":0,"credit_card":{"nonce":"${creditCardToken}","expiration_month":"03","expiration_year":2019},"paypal":null}} Request Body in View Results Tree for the above request: {"order":"{\"id\":0,\"order_date\":\"3/8/2019\",\"order_data\":{\"items\":[{\"id\":1876318,\"quantity\":1,\"name\":\"Air Filter\",\"price\":8.54,\"retail_price\":8.54,\"msrp\":0.0,\"price_level\":{\"price_level_id\":1,\"price_level\":\"RETAIL\",\"retail_multipler\":1.00,\"description\":\"Regular retail\",\"price_type\":{\"price_type_id\":1,\"price_type\":\"Regular\",\"label\":\"\"}},\"is_hazmat\":false,\"is_accessory\":false,\"oversize_category_id\":null,\"oem_number\":\"W10311524\",\"image_url\":\"https://www.redacted.com/dbImages/i/00004039/Air-Filter-W10311524-01215703.jpg\",\"quantity_by_dc\":[{\"id\":1,\"quantity\":0},{\"id\":2,\"quantity\":0}],\"repair_time\":null,\"repair_savings\":null,\"skill_level\":1,\"labor_hours\":null,\"prodcut_categories\":[{\"id\":1,\"name\":\"Appliances\"}]}],\"email\":\"test12@example.com\",\"billing_address\":{\"first_name\":\"John\",\"last_name\":\"Doe\",\"street1\":\"2600 S River Rd\",\"street2\":\"\",\"city\":\"Des Plaines\",\"state\":\"IL\",\"country\":\"US\",\"zipcode\":\"60018\",\"phone\":\"1231231234\",\"ext\":\"\",\"business_name\":\"\",\"is_business_address\":false,\"is_po_box\":false},\"shipping_address\":{\"first_name\":\"John\",\"last_name\":\"Doe\",\"street1\":\"2600 S River Rd\",\"street2\":\"\",\"city\":\"Des Plaines\",\"state\":\"IL\",\"country\":\"US\",\"zipcode\":\"60018\",\"phone\":\"1231231234\",\"ext\":\"\",\"business_name\":\"\",\"is_business_address\":false,\"is_po_box\":false},\"shipping_choice\":{\"shipping_option_id\":1,\"ship_to_po_box\":false,\"is_saturday_delivery\":false,\"ship_complete\":true,\"is_home_business\":false},\"total\":15.71,\"discount\":0.0,\"subtotal\":8.54,\"shipping_charge\":6.25,\"offshore_surcharge\":0.0,\"saturday_shipping_surcharge\":0.0,\"saturday_shipping_surcharge_for_ship_method\":15.00,\"oversize_surcharge\":0.0,\"weight_surcharge\":0.0,\"international_processing_fee\":0.0,\"sales_tax\":0.92,\"sales_tax_label\":\"Estimated Sales Tax\",\"purchase_order_number\":null,\"promotion_code\":\"\",\"device_data\":\"{\\"device_session_id\\":\\"6E0E291D4A295930E103D3F89D9DA58F\\",\\"fraud_merchant_id\\":\\"600000\\"}\",\"is_promo_code_valid\":false},\"sop_number\":\"\",\"security_code\":null,\"rc_order_form\":\"\",\"o_checksum\":\"7AB4149F2F0E47E9A3F7546FB0E21ABD\",\"rc_checksum\":\"703BE7B71AA016C82132378323E98B9E\"}","payment":{"payment_type_id":0,"credit_card":{"nonce":"tokencc_bd_v3q2pq_nr8xwy_w8k5dt_qcvdvw_yxy","expiration_month":"03","expiration_year":2019},"paypal":null}} Seems like JMeter converts \\\"device_session_id\\\" to \\"device_session_id\\" (with the latter being invalid JSON). Please let me know if you need more information. Sorry about the big wall of text. Thanks, uTosTan
Do you mind providing a simple .jmx file or Results Tree script so I can replicate this myself? I feel I can help fix this if I'm able to replicate what you are experiencing. Having trouble understanding based on your post alone
Created attachment 37249 [details] incorrect multiple-backslash processing in request body simple JMX, proving that POST request body is being sent "as is", until you add any ${var}. Then it start "fixing" the double-backslashes, and m.b. other chars too.
simple jmx attached, just check what it actually tries to send in tree view for both requests The post request body {"field","value\\value"} is sent exactly as {"field","value\\value"} While {"field${__threadNum}","value\\value"} is sent as {"field1","value\value"}
Jmeter 5.3 still has this problem
Same issue here. Apparently, the problematic code is within `FunctionParser.compileString(String value)` method. As stated in javadoc: "Removes escapes from '$', ',' and '\'." This is why it's working perfectly fine when no variable is used.
Pull request to fix the issue: https://github.com/apache/jmeter/pull/616 I'm not sure of the overall impact of this modification. It now allows multiple '\' without removing any of them, as long as it's not in front of a `$` or a `,`.